Anyone who has ever waited in dread to have a root canal may find some comfort in the findings of a new brain-imaging study.

For some people, researchers say, the waiting is indeed the hardest part, and finding a distraction might help.

Their study, published in the journal Science, used a brain-imaging technique called functional MRI to investigate the neural mechanisms underlying dread - specifically the agony of waiting to have a painful procedure.

It found that among 32 volunteers who agreed to have a series of shocks to the foot, some of them dreaded each shock so much that they repeatedly opted to have a higher-voltage jolt just so they could get it over with more quickly.

These individuals, dubbed “extreme dreaders,” showed greater activity in a brain region related to both pain and attention. The findings, say the researchers, indicate that dread arises not from simple fear, but from the brain’s attention to the unpleasant event.

“The dread is often worse than the event itself,” said lead study author Dr. Gregory S. Berns, a professor of psychiatry and behavioral sciences at Emory University School of Medicine in Atlanta.

The brain-imaging results are “good news,” he told Reuters Health, because they indicate that extreme dreaders can do something to alleviate the problem: find a distraction - such as meditation, exercise or some other activity - to take the focus off the anticipated event.

For the study, Berns and his colleagues took brain images of volunteers who agreed to endure Electrical shocks to their feet. First, each jolt was preceded by a cue that told participants how intense it would be - 60 percent of their maximum pain tolerance, for instance - and how long they would have to wait for it.

In a second go-around, participants were presented with choices on how each shock should be delivered, with the voltage and timing of the jolt as the variables. For example, they could choose between having a shock at 90 percent of their maximum pain tolerance delivered in the next 3 seconds, or one at 60 percent intensity in 27 seconds.

Of the 32 volunteers, nine - the extreme dreaders - consistently opted for the stronger shock in order to avoid the longer wait.

This may seem illogical to many people, Berns said, but for extreme dreaders avoiding the anguished wait makes sense.

And it was the extreme dreaders who showed particularly high activity in the brain’s so-called pain matrix during the build-up to their Electrical shocks - specifically, in areas related to attention, but not those associated with fear and anxiety.

In other words, extreme dreaders were giving more attention to their foot than “mild dreaders” were.

So finding a distraction may be the best way for extreme dreaders to deal with the wait for a medical procedure, Berns said. This, he noted, is something many people have “subjectively” known, but the new findings reveal the brain basis for it.

SOURCE: Science, May 5, 2006.