What part of the brain does addiction start in?

Each substance has slightly different effects on the brain, but all addictive drugs, such as alcohol, opioids and cocaine, produce a pleasant surge of the neurotransmitter dopamine in a region of the brain called the basal ganglia; neurotransmitters are chemicals that transmit messages between nerves Cells. These images show how scientists can use imaging technology to measure brain and heart function. Higher activity is shown in reds and yellows, and reduced activity in blues and purples. Both healthy brains and hearts are more active than sick brains and hearts, because both addiction and heart disease cause changes in function.

In drug addiction, the frontal cortex, in particular, shows less activity. This is the part of the brain associated with judgment and decision-making (NIDA). Addiction affects the brain on many levels. The chemical compounds in stimulants, nicotine, opioids, alcohol, and sedatives enter the brain and bloodstream when used.

Once a chemical enters the brain, it can cause people to lose control of their impulses or to want to consume a harmful substance. Addictions focus on alterations in the mesolimbic dopamine pathway of the brain, also known as the reward circuit, which begins in the ventral tegmental area (VTA) above the brain stem. The cell bodies of dopamine neurons arise in the VTA and their axons extend to the nucleus accumulbens. This center located in the center connects with many other brain structures, such as the limbic system (the so-called emotional brain, in evolutionary terms, very old).

Some dopamine fibers are also projected onto a much newer structure, the prefrontal cortex, which participates in cognitive tasks such as memory, planning, attention and social behavior. Illustration courtesy of the National Institute on Drug Abuse at the National Institutes of Health. The brain will begin to recover the volume of gray matter lost one week after the last alcoholic drink. Other areas of the brain and the white matter of the prefrontal cortex take several months or longer to recover.

This area is a traffic hub for signs to and from the addiction pathway and other parts of the brain. What the study suggests, Caron says, is that addiction doesn't depend solely on cocaine's ability to increase dopamine levels. A person addicted to heroin may be in danger of relapsing when they see a hypodermic needle, for example, while another person may start drinking again after seeing a bottle of whiskey. Addiction is a complex illness that alters a person's ability to maintain control of the various substances used.

Researchers, doctors and addiction treatment professionals can use brain scanning technology to identify areas of the brain that have been altered by addiction. People who develop an addiction find that the drug no longer gives them as much pleasure as before and that they have to take larger amounts of the drug more often to feel high. The plasticity of the brain is impressive and necessary to make positive changes; unfortunately, it can also adapt to form unhealthy habits, associations and addictions. Conditional learning helps explain why people who develop an addiction are at risk of relapsing even after years of abstinence.

Genetic factors, environmental factors and, most importantly, the intricate and yet mysterious interaction of the two are supposed to be fundamental to the addiction process. At this stage, the individual may not have a full-fledged addiction; however, tolerance or dependency may have developed. Electroencephalograms are generally used to help people who have suffered traumatic brain injuries and may be useful for people with obsessive compulsive disorder and other brain disorders. Detoxification can take several days to several weeks, depending on the substance and how long a person has struggled with addiction.

Research is not yet fully clear exactly which part of the brain controls addiction, as it probably depends on many different factors. Drug-related signals did not cause brain activation in control subjects (scans not shown), but volunteers who experienced a high level of signal-induced cocaine craving showed brain activation in the dorsalateral prefrontal cortex (DL; upper scintigraphs), which is important in short-term memory, and in amygdala (AM; lower scintigraphy), which is involved in emotional influences on memory. Because desire and reinforcement are aspects of learning, it's not surprising that addiction researchers are interested in glutamate, the neurotransmitter most associated with the learning process. .

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