The Brain: The Flavor Of Memories

Emotions turn out to be key in how we remember--and can help us recast traumas dredged from the past

By Michael D. Lemonick Friday, Jan. 19, 2007

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    That's consistent with McGaugh's ideas, but there are only a few bits of hard evidence so far to support it. One bit comes from Israel: researchers found that of people who showed up at emergency rooms after traumatic events, those admitted with the fastest heartbeats had the highest risk of later developing PTSD. Another is the surprising fact that after an accident there's a much higher rate of PTSD in those with paraplegia (paralysis of the lower body) than in those who suffer quadriplegia (paralysis of all four limbs). "It doesn't make any psychological sense," says Pitman. But it makes physiological sense because quadriplegia severs the link between the brain and the adrenal glands.

    To test his theory, Pitman went to the the emergency room at Massachusetts General Hospital in Boston and intercepted patients who had suffered serious traumas. He gave some of them propranolol, a drug that interferes with adrenaline uptake. The rest got placebos. He also had them tape-record accounts of the traumas. When he played back the tapes eight months later, eight of 14 placebo patients developed higher heart rates, sweaty palms and other signs of PTSD. None of the patients on the real drug had such responses.

    Encouraged by his results, Pitman is entering the third year of a much larger trial--one that has stirred some controversy. The President's Council on Bioethics recently condemned his study as unethical, saying that erasing memories risks undermining a person's true identity. Pitman rejects such notions as a bias against psychiatry. After all, he says, no one suggests that doctors should withhold morphine from people in acute pain on the grounds it might take away part of the experience.

    Other researchers are looking at PTSD as well. Michael Davis, a professor of psychiatry at Emory University in Atlanta, is about to launch a study of at least 120 soldiers returning from Iraq to see whether a compound called D-cycloserine could help prevent PTSD. This compound activates a protein that helps the mind form new, less emotional associations with the original trauma, letting patients tolerate the memory better. Studies in rats and humans have shown that it can work--and, says Davis, "psychologists are very excited by it."

    That's because the theory behind D-cycloserine's action is totally consistent with old-fashioned talk therapy, and especially with cognitive behavioral therapy (CBT), currently the most effective nondrug technique dealing with phobias, PTSD and obsessive-compulsive disorder. The idea behind CBT--which first appeared in the 1950s, long before neuroscience could explain such things--is that the patient examines upsetting ideas and consciously assigns new, more positive associations to them. Even old-fashioned Freudian psychotherapy might fit in with this model. By dredging up forgotten memories, it may achieve the same thing, albeit in a much less efficient way.

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