Dani and Montague Article Summary

Posted by on July 9, 2011

Tobacco use is one of the major causes of death in the world.  Half of the world’s smokers will be killed by tobacco eventually if they do not quit.  The paper by Dani and Montague, “Disrupting Addiction through the Loss of Drug-Associated Internal States,” introduces the addictive problems of tobacco and drugs, and posits a possible situation that may remove them.  In this paper I will discuss how the authors use the upcoming evidence of several scientific findings to prove their claim that lesion to the insula region of the brain allows some smokers to quit easily and without relapse.

People generally recognize the harmful and fatal effects of long-term tobacco use.  In fact, “about one third of them attempt to quit each year, but less than 10% of those succeed.”  Nicotine is a major addictive component of tobacco, as it by itself causes people to continually self-administer the drug, and the lack of which creates a withdrawal syndrome solved only by nicotine replacement.  The authors suggest that there might be a possible solution.  They cite a scientific article recently published which stated evidence that some stroke patients who received damage to the insula region of their brains were able to easily stop smoking.

The authors state that, due to the location of the insula in the brain, it is highly possible for the insula to be involved in the integration of sensory information, emotional information, and conscious feelings.  The authors believe the insula participates in the “process of establishing a continually updated representation of our internal state.”  This internal state acts according to learned behaviors and, in view of smoking, according to learned drug associations.  If a person was to develop a smoking habit before or after a certain meal, then it would become a learned habit that the insula region of the brain stores.  Such stored behavioral associations are what make quitting smoking so difficult, because even when one attempts, the insula recreates the urges that had been stored and associated with daily activities like eating when the person used to smoke; therefore, to relieve the urge, the person must smoke.

This drug addictive system reacts so because drug use overtakes naturally adaptive systems within humans which lead to reward/success.  For example, a food advertisement seen on the television induces the internal state of hunger, which in turn influences the behavior to eat in order to satiate that state.  Addictive drugs, like nicotine, hijack this natural system and influence it in such a way that the environments and situations, in which the individual developed the learned behavior of smoking, become essential addictive cues which heavily influence smokers trying to quit to relapse.

In a study of 69 patients with brain lesions, in which 16 had insula lesions, the 12 of 13 smokers with insula lesions that quit were reported to have not had any relapse and lost the desire to smoke.  This is enormous because it shows, as consistent with other studies, that there is a plausible relationship between insula activity and cue-induced drug cravings.  The authors state accumulating evidence that the environment which the smoker is in when they decide to smoke is important because that environment becomes associated with the behavior of smoking and remains part of the internal state.

According to the authors, a recent fMRI showed how cues, such as environment or daily activities associated with smoking, produce neural activity in areas of brain related to memory, emotion, and motivation.  Since these activities were earlier said to be related to the area of the brain called the insula, this would mean that the insula is more probably linked to cue-induced cravings.  Essentially this translates into “events and processes associated with the addictive drug (for example, the environment during drug taking) [becoming] linked to the acquisition and delivery of drug, making them salient cues that prompt the desire for the drug,” (Dani and Montague 2).  In labs tests, rats were shown to relapse when presented with the same nicotine-associated cues that had previously been removed.

In essence, the research has shown that drug addiction has the ability to manipulate normal neuronal methods of learning and memory, which can lead to long term changes in behavior, changes that accumulate as the addiction continually progresses.   Furthermore, aforementioned research has shown brain lesions to the insula allow patients to often quit smoking easily without the consequential and detrimental desire to smoke.  Lastly, though research shows “that learned drug associates can cue internal states that perpetuate addiction.”  Research has also successfully shown that lesions to the insula disallow for learned associations to have effect on the patients’ desire to smoke.

Though the evidence and research presented by the authors is convincing, I believe the authors’ research does not completely support their hypothesis that insula lesions may remove drug addiction.   This is mainly because there are not nearly enough patients tested for the evidence to be credible for the entire population of human beings.  It is understandable that the number of patients for them to study is limited, and that is why I believe the authors’ research validates the continual research in that area, but should not be taken as a true theory yet.  This hypothesis must remain in the experimental phase until substantial evidence is found.

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