Blue Smoke Blues

The dangers of cigarette smoking are a constant topic to which most of us nod wisely and switch off, whether we’re smokers or non-smokers. The stress on cancer, heart disease and pulmonary problems dominates. But we should remember that the ingestion of nicotine is an addiction and that its affect on the brain is at least as relevant.

 With a nod in that direction, Yu et al have stuffed three-quarters of a pack of heavy smokers into the big magnet (1). They used a similar number of controls, of course. The “heavy” designation meant that the chronic smokers smoked a pack of 20 each day and had been smoking for at least 15 years.

The gray and white matter volumes were recorded for the various regions of the brain. The heavy smokers had less in the cerebellum but more in their putamen. The blood flow in the cerebellum of each heavy smoker increased after smoking indicating an increase in activity.

Remember that the gray matter is made up of the neurons with the axons or tails which transmit the signals being the white matter. So a smaller volume wouldn’t seem to be a good thing. The cerebellum is associated with your motor control, so smoking to help you concentrate on that fine painting or assembly task puts you in an interesting quandary. The stimulated activity indicated by the blood flow looks good, but overall the progressive volume reduction may be a high price.

The putamen has high dopamine (a pleasurable hormone) content and a larger amount of material here may make you grin a little more. This region also seems to be involved with your dislike of people and the way you react to them so you might end up smiling for a few minutes before returning to your usual grouchy, hard-bitten personae. Ah, time for another cigarette!


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