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smoking is a thing in the head…

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Brain Scans Reveal Cause Of Smokers’ Cravings

We all knew it: within the mind of every smoker trying to quit rages a battle between reason wanting to break the habit and the screaming for another cigarette. More often than not, that cigarette gets lit.

smoker_brain.jpg

Researchers at Duke University Medical Center studied brain scans of smokers discovering three specific regions deep within the brain that appear to control dependence on nicotine and craving for cigarettes. Shown in blue in this illustration is the thalamus, an region of the brain critical to one’s ability to calm down when stressed. In red is the striatum, a region implicated in the pleasure system of the brain. In green is the anterior cingulate cortex, a region vital to self-control and concentration. (Credit: Image courtesy of Duke University Medical Center)

These regions play important roles in some of the key motivations for smoking: to calm down when stressed, to achieve pleasure and to help concentration.

“If you can’t calm down, can’t derive pleasure and can’t control yourself or concentrate, then it will be extremely difficult for you to break the habit,” said lead study investigator Jed E. Rose, Ph.D., director of the Duke Center for Nicotine and Smoking Cessation Research. “These brain regions may explain why most people try to quit several times before they are successful.”

In this study, the researchers manipulated the levels of nicotine dependence and cigarette craving among 15 smokers and then scanned their brains using positron emission tomography, or PET scans, to see which areas of the brain were most active.

Three specific regions of the brain demonstrated changes in activity when the smokers craved cigarettes versus when they did not.

One region that lights up, called the thalamus, is considered to be the key relay point for sensory information flowing into the brain. Some of the symptoms of withdrawal among people trying to quit stem from the inability to focus thoughts and the feeling of being overwhelmed, and could thus be explained by changes in this region, according to the researchers. The researchers found that changes in this region were most dramatic among those who said they smoked to calm down when under stress.

Another region that lights up is a part of the pleasure system of the brain. Changes in this region, called the striatum, were most notable in people who smoked to satisfy craving and for pleasurable relaxation, the researchers said.

A third region that lights up, called the anterior cingulate cortex, is vital to cognitive functions such as conflict, self regulation, decision making and emotion. People whose brain scans showed the most differences in this region also reported that they smoked to manage their weight.

here is the original Entry in Pubmed :

Neuropsychopharmacology. 2007 Mar 14; [Epub ahead of print]

Regional Brain Activity Correlates of Nicotine Dependence.Rose JE, Behm FM, Salley AN, Bates JE, Coleman RE, Hawk TC, Turkington TG.
1Department of Psychiatry, Duke University Medical Center, Durham, NC, USA.

Fifteen smokers participated in a study investigating brain correlates of nicotine dependence. Dependence was reduced by having subjects switch to denicotinized cigarettes for 2 weeks while wearing nicotine skin patches. Positron emission tomography (PET) scans assessed regional cerebral metabolic rate for glucose (rCMRglc) after overnight nicotine abstinence on three occasions: (1) at baseline; (2) after 2 weeks of exposure to denicotinized cigarettes+nicotine patches; and (3) 2 weeks after returning to smoking the usual brands of cigarettes. Craving for cigarettes and scores on the Fagerstrom Test of Nicotine Dependence (FTND) questionnaire decreased at the second session relative to the first and last sessions. Regional brain metabolic activity (normalized to whole brain values) at session 2 also showed a significant decrease in the right hemisphere anterior cingulate cortex. Exploratory post hoc analyses showed that the change in craving across sessions was negatively correlated with the change in rCMRglc in several structures within the brain reward system, including the ventral striatum, orbitofrontal cortex and pons. The between-session difference in thalamus activity (right hemisphere) was positively correlated with the difference in FTND scores. Correlational analyses also revealed that reported smoking for calming effects was associated with a decrease (at session 2) in thalamus activity (bilaterally) and with an increase in amygdala activity (left hemisphere). Reported smoking to enhance pleasurable relaxation was associated with an increase in metabolic activity of the dorsal striatum (caudate, putamen) at session 2. These findings suggest that reversible changes in regional brain metabolic activity occur in conjunction with alterations in nicotine dependence. The results also highlight the likely role of thalamic gating processes as well as striatal reward and corticolimbic regulatory pathways in the maintenance of cigarette addiction.Neuropsychopharmacology advance online publication, 14 March 2007; doi:10.1038/sj.npp.1301379.

PMID: 17356570 [PubMed – as supplied by publisher]

Written by huehueteotl

March 23, 2007 at 9:54 am

One Response

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  1. […] the University of Bordeaux 1, have analysed the subtle balance between various types of nicotinic receptors in the brain during chronic exposure to nicotine. Their research, just published in PNAS, could make it possible […]


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