They are smokers. Then the strokes overcame their addiction.

Injured brain scans often create a map of irreversible loss, revealing points of damage that make memory difficult or concussive.

But in rare cases, those scans can reveal the opposite: the area of ​​the brain where the injury miraculously relieves some of the symptoms, offering clues as to how the doctor might do the same.

Researchers are now looking at a series of images of the compound, which came from nicotine-addicted smokers whose strokes or other injuries helped them recover. The results, scientists say, show a network of interconnected brain regions that they believe underpins drug-related disorders affecting tens of millions of Americans.

The study, published in the journal Nature Medicine on Monday, supports the recently rising concept: addiction does not live in one brain area or another, but rather in a regional circuit connected by threaded nerves.

The results may provide clearer targeting for the treatment of drugs that send pulses to the brain, a new technique that shows promise in helping people quit smoking.

“The biggest problem with addiction is that we do not know where in the cell is the main problem we should be targeting with therapy,” said Dr. Juho Joutsa, one of the university’s leading educators and neuroscientists. Of Turku in Finland. “We hope then, we have a good idea of ​​those regions and networks.”

Research over the past two decades has solidified the notion that addiction is a disease of the brain. But many still believe that addiction is addictive.

Some independent experts say the latest study is an unusually powerful manifestation of the role of the brain in substance use disorders. Among smokers with stroke or other brain injury, those with neural network damage in particular experience immediate relief of their cravings.

The researchers simulated their findings in a separate group of patients with brain injury who completed an alcohol risk assessment. The brain network associated with a lower risk of alcoholism is similar to the one that reduces nicotine addiction, suggesting that the cycle may underlies a broad set of satisfactions.

“I think this is probably the most influential publication not just of the year, but of the decade,” said A. Thomas McLellan, professor of emeritus of psychiatry at the University of Pennsylvania and former deputy director of the National Institutes of Health. Control policy, those who were not involved in the study. “It makes a lot of breaks that are still prevalent in the field of addiction: addiction is a nurturing, addiction is a weak personality, addiction is immoral.”

In recent years, ongoing studies have identified areas of the brain specifically where the injury, or trauma, seems to be associated with addiction relief. But targets remain unchanged.

Dr Hamed Ekhtiari, a clinical therapist at the Laureate Institute for Brain Research in Tulsa, Okla, said: “People are not successful in showing consistency in their respective fields.

In a new study, Dr. Joutsa applied a statistical technique that complements the old set of brain scans from smokers in Iowa with traumatic brain injury. An earlier analysis of the same scan suggested that patients with damage to the insula, the brain region associated with cognitive stimulation, became more likely to quit smoking.

But Dr. Joutsa, back in the same phase scans pixel by pixel, noticed that many patients without insula injuries have lost the urge to smoke. “There is something in the insula story, but it is not the whole story,” he said.

Working with Dr. Michael Fox, a professor of neuroscience at Harvard Medical School, Dr. Joutsa examined a second set of scans from all smokers who suffered a stroke in Rochester, NY, they looked at 129 cases.

The team tried to find areas of the individual brain where the injury could help the patient quit smoking. Instead, researchers turned to standardized diagrams of brain connections that showed that activity in one region was related to activity in another.

Researchers can immediately find a network of brain-connected regions where the injury results in immediate relief from nicotine cravings and other networks in which the injury does not.

“What we recognize in many different areas is that our therapeutic goals are not regions of the brain, as we used to think, but interconnected brain circuits,” said Dr. Fox. “If you consider how the brain connects, you can improve healing.”

The study did not take into account how patients’ lifestyles – how often they were exposed to tobacco – for example – may affect their habits. Patients who were considered to have relieved their addiction after their injury generally quit smoking immediately, reported no urge to smoke and did not start again while they were being monitored.

However, researchers have looked at how other trauma-related changes – cognitive or emotional, for example – could help explain the disappearance of nicotine cravings in some patients. In the end they do not seem to make a difference.

External experts say some of the brain networks listed in the study are familiar to them from previous research. Dr. Martijn Figee, a psychiatrist at the Center for Advanced Cycle Therapy at Mount Sinai in Manhattan, studies how electrical stimulation to the brain can treat complex disorders, depression and addiction. He said addiction generally seems to be related to the activity of the cognitive control cycle of the brain and the excessive activity of the reward-related cycle.

By applying electrical stimulation to the surface of a patient’s head or using more aggressive methods such as deep brain stimulation, the doctor can suppress activity in certain areas, strip the effects of trauma, and excitatory activity in others. The study identified a region, called the medial frontopolar cortex, that seemed to be a good candidate for excitatory stimulation; That region overlaps with the goal of a recently approved regulator-approved treatment to help smokers.

The treatment uses an electromagnetic tube to bury the patient in the patient’s head to deliver an electric current to the surface of the patient. Other techniques involve implanting electrodes into certain areas of the brain or permanently shutting down the brain.

“This paper is really interesting as it points to a clearly accessible goal” for the treatment, Dr. Figee said.

While brain stimulation has become commonplace for the treatment of depression and obsessive disorder, the use of addiction therapy is slower to catch on. Researchers say it will take years to upgrade the technique.

Although studies have shown that electrical or magnetic stimulation can reduce cravings for a substance, it is not clear how long those effects will last. Some of the dominant goals are deep in the brain; Access to them can require deep brain stimulation or a specific type of tube that is only recently available, Dr. Figee said.

Knowing where to stimulate the brain directly does not solve the question of how often to use it, scientists say. And the connections are different in the brains of different people, raising the prospect of the need for a medical solution.

“People who are addicted are more likely to receive brain stimulation later than those who are depressed or have bipolar disorder,” the researchers said.

There may be structural challenges. Judy Luigjes, an assistant professor of psychology at the University of Amsterdam Medical Center, has been replaced by a pool of thousands of patients at a substance abuse treatment center in the Netherlands for deep brainstorming studies. At three years, only two patients started the trial.

Dr. Luigjes and her colleagues write that patients with substance abuse disorders may avoid the procedure in part because their motivation to deal with the disorder is greater than it does in patients with obsessive compulsive disorder.

And the much instability that often accompanies substance use disorders can make investing in time-consuming treatments difficult. Only one-third of patients who had an appointment with the research team brought a family member or friend, Dr. Luigjes found.

Some scientists are working to address those concerns. For example, the drug team at Mount Sinai, performing less brainstorming sessions with patients at home or in community centers rather than in hospitals, reduced barriers to treatment.

But while the brain may be the gateway to addiction treatment, Dr. Luigjes says it may not be the most important thing. Other scientists, too, have argued in recent years that focusing on the psychiatric form of addiction has diverted attention and money from research addressing the social and environmental factors that cause addiction.

“We took too much of our hopes and money and energy,” she said, referring to the focus on brain stimulation. “I do not know if it will pay off the way we thought it would.”

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