Waiting for the pain ...

Anticipation may be just as bad as the real thing

May 05, 2006|By DENNIS O'BRIEN | DENNIS O'BRIEN,SUN REPORTER

How much pain can you take? It may be a case of mind over matter, experts say.

Brain scans of volunteers given a series of electric shocks demonstrated a variety of reactions. Some dreaded each successive shock, while others managed to keep what was coming out of their minds, according to a team of Atlanta researchers whose study was published today.

Volunteers who dreaded the pain most were willing to endure more intense pain if they could get it over with quickly. Those who kept their minds off the impending shocks were willing to wait longer -- and endured less intense shocks as a result, the researchers say.

The study may help scientists determine how a fear of pain plays out in everyday decisions, such as whether to invest in a stock or schedule a dental appointment, said Dr. Gregory S. Berns, a physician and neuroscientist at the Emory University School of Medicine who led the study. The findings were published today in the journal Science.

"It shows us the way to wait for something unpleasant, that it helps if you have an ability to distract yourself and take your mind off the negative aspects while waiting," Berns said. "Think about something else during the waiting period and you'll actually make better decisions."

In the experiment, 32 volunteer participants in their 20s, 30s and 40s had their left feet wired to electrodes while they were inside a brain scanner. They were observed during the electrical shocks and for up to 30 seconds before each zap. Participants were paid $40 and received 96 shocks.

Researchers told each volunteer ahead of time about the intensity of the shocks and the interval between them. Waiting periods ranged from one to 27 seconds. The intensity of the shocks ranged from a mild charge to a painful jolt similar to the shock from a wall socket, Berns said. All shocks lasted less than a second.

"It felt like a quick needle prick to the foot," Berns said.

The researchers confirmed earlier findings that the anticipation of the shock and the jolt itself activated the same areas of the brain. They also found that a majority of the participants wanted to avoid delaying the shock and agreed to reduce the waiting time as long as the shock level remained the same.

But a quarter of the participants dreaded the wait so much that they agreed to even more intense shocks if it meant that they were over sooner, Berns said. The researchers classified the group as "extreme dreaders."

In follow-up scans, the researchers found the pain centers in the brains of the extreme dreaders activated earlier during the waiting periods than those who worried less. Essentially, they thought more about the coming shock, were more anxious about it and were more willing to bargain to shorten the waiting period, Berns said.

"What we're trying to understand is what happens in the decision-making process while you're waiting for the outcome of that decision," he said. "What we see is that dread plays a major role."

Experts say the study could help scientists understand anxiety disorders and develop treatments for coping with fears about public speaking, air travel and other common phobias.

"Most of the pain and even the pleasure of some events, like a wedding, comes from the planning and the aftermath, not the actual event," said Colin F. Camerer, a professor of business economics at the California Institute of Technology in Pasadena, who was not involved in the study. "What this illustrates, or shows, is the feasibility of seeing that there is an effect in the brain, just by the thought of something coming up."

Experts have known for years that many of the same areas of the brain activated by pain are also activated by the anticipation of it. Expectations color our perception of pain, they say.

"What you think about an impending stimulus is a major factor in how you perceive it," said Robert C. Coghill, a researcher at Wake Forest University School of Medicine in Winston-Salem, N.C. Coghill co-authored a study last year that found a 28 percent reduction in brain scan activity and pain levels reported among volunteers who were told to expect a moderate heat pulse on their legs but actually got more intense heat.

Berns said his work also is focused on trying to determine why some people make bad decisions, such as choosing to sell off a stock at the first sign of a decline rather than waiting out an economic downturn. The stock seller could be dwelling on the stock's fate too much, he said.

"The key to the decision-making process is how we think we're going to feel while we're waiting," Berns said. "But that's something that's not included in most economic models of decision making."

dennis.obrien@baltsun.com

Baltimore Sun Articles
|
|
|
Please note the green-lined linked article text has been applied commercially without any involvement from our newsroom editors, reporters or any other editorial staff.