SCIENCE
Notebook
Monday, January 29, 2007; Page A06
Brain Damage Aided Smokers in Quitting
What if quitting smoking didn't involve fighting the urge to smoke over and over and over? Would that make it easier for smokers to kick the habit?
Definitely.
That's the conclusion of a study of stroke survivors whose brain damage let them quit smoking seemingly effortlessly.
Antoine Bechara and Nasir H. Naqvi, neuroscientists at the University of Iowa medical school, compared 19 smokers whose strokes had destroyed a part of the brain called the insula with 50 smokers whose strokes damaged other brain regions. Previous research had revealed the insula to be involved in anticipating and responding emotionally to physical sensations.
The researchers found that people who had strokes affecting the insula were not significantly more likely to quit than those who had strokes elsewhere in the brain, but those who did quit had much less difficulty doing so.
Bechara and Naqvi found that 12 of the 13 insula-damaged patients who stopped smoking said they had no trouble doing so. One told them that "my body forgot the urge to smoke." By comparison, only four of the 19 patients without insula damage who quit smoking did so without cravings or relapses.
The scientists think that destruction of the insula may take away the pleasant anticipation of the cigarette and the relief from withdrawal symptoms that comes with each drag.
Missing from the report was mention of other effects of insula damage. The study appeared last week in the journal Science.
-- David Brown
Mercury Ubiquitous In Fish in the West
Every one of 2,700 fish taken from 600 rivers and streams in the western United States and tested for mercury between 2000 and 2004 contained the toxic metal, a study found.
While the mercury amounts were below the levels considered hazardous to humans, researchers from Oregon State University and the Environmental Protection Agency said they were surprised by how prevalent the substance had become. The mercury could seriously threaten fish-eating birds and mammals.
"If I were a mink or an otter, I'd be concerned," said Oregon State's Robert M. Hughes, an author of a paper in last week's issue of the journal Environmental Science and Technology. "Those guys are loading up on fish containing mercury, and we don't really know at what levels they may be affected."
Fish from 93 percent of the rivers and streams contained more mercury than is considered clearly harmless.
The scientists found that mercury levels were generally higher in larger species that feed on smaller fish, a group that includes bass, walleye and northern pike. Mercury is known to build up in animal tissues.
Because the mercury was found throughout the 12 states sampled, the researchers said, the source was probably atmospheric pollution. At high levels, it can cause neurological damage.
-- Marc Kaufman
