The more someone smokes, the smaller the number of gray cells

To investigate the relation between cortical thickness and nicotine dependence, the brains of 22 smokers and 21 people who have never smoked in their lives were investigated with the aid of a magnetic resonance tomograph. The measurements were carried out at PTB in Berlin and furnished high-resolution three-dimensional images of the brain structure.

On the basis of these data, the individual thickness of the cortex could be determined at the Charité by means of a special evaluation procedure. A comparison of the two groups showed that in the case of smokers, the thickness of the medial orbito-frontal cortex is, on average, smaller than in the case of people who have never smoked. The thickness of this region decreased in relation to the increase in the daily consumption of cigarettes, and depending on how long in their lives the participants in the study had been smokers.

Cause and effect are, however, still not clear. Although it is known from animal experiments that nicotine changes the development of the brain and leads to a damaging of neurocytes, it cannot be ruled out that the reduced thickness of the frontal cortex region found in the case of the participants in the study already existed before they started smoking. Possibly, it is a genetically conditioned predisposition for nicotine dependence. Scientists want to find out in future studies whether the brain structure of smokers can become normal again after they have given up smoking.

More information: Kühn, S.; Schubert, F.; Gallinat, J.: Reduced thickness in medial orbitofrontal cortex in smokers. Biological Psychiatry, 2010 Sept 25 (Epub ahead of print)

Provided by Physikalisch-Technische Bundesanstalt