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UNIT3 A PILL TO FORGET

(CBS) If there were something you could take after experiencing a painful or traumatic event that would permanently weaken your memory of what had just happened, would you take it? As correspondent Lesley Stahl reports, it’s an id ea that may not be so far off, and that has some critics alarmed, and some trauma victims

filled with hope.

"I couldn't get my body to stop shaking. I was trembling, constantly trembling. Memories of it would just come back, reoccurring over and over and over," subway

conductor Beatriz Arguedas recalls.

Last Sept. 30, Beatriz was driving her normal route on the Red Line in Boston when one of her worst fears came to pass: "Upon entering one of the busiest stations, a man jumped in front of my train, to commit suicide," she explains.

Beatriz saw the man jump. "We sort of made eye contact and then I felt the thud from him hitting the train and then the crackling sound underneath the train and, then, of course, my heart starts thumping," she recalls.

"She came into our emergency room afterwards, very upset. No physical injury. Entirely a psychological trauma," says Dr. Roger Pitman, a psychiatrist at Harvard Medical School who has studied and treated patients with post-traumatic stress

disorder, or PTSD, for 25 years.

"They're caught up so much with this past event that it's constantly in their mind," Pitman explains. "They're living it over and over and over as if it's happening again.

And they just can't get involved in real life."

When Beatriz arrived in the emergency room, Pitman enrolled her in an experimental study of a drug called propranolol, a medication commonly used for high blood pressure ... and unofficially for stage fright. Pitman thought it might do something almost magical – trick Beat riz’s brain into making a weaker memory of the event she

had just experienced.

In the study, which is still under way, half the subjects get propranolol; half get a

placebo.

Asked whether he knows if Beatriz got the drug or the placebo, Dr. Pitman says he has no idea and neither does she, and that the research team won't know for

another two years.

If Pitman is right, the results could fundamentally change the way accident victims,

rape victims, even soldiers are treated after they experience trauma.

The story begins with some surprising discoveries about memory. It turns out our memories are sort of like Jello – they take time to solidify in our brains. And while they're setting, it's possible to make them stronger or weaker. It all depends on the

stress hormone adrenaline.

The man who discovered this is James McGaugh, a professor of neurobiology at the

University of California, Irvine.

McGaugh studies memory in rats, and he invited Stahl to watch the making of a rat memory – in this case how a rat who's never been in this tank of water before learns how to find a clear plastic platform just below the surface.

"He’ll swim around randomly," McGaugh explains. The rat cannot see the platform,

since his eyes are on the top of his head.

The rat will swim around the edge for a long time, until eventually he ventures out and by chance bumps into the platform. The next day, he'll find the platform a little

bit faster.

But another rat, who had learned where the platform was the day prior, and then received a shot of adrenaline immediately afterwards, today swam instantly to the

platform.

Adrenaline actually made this rat's brain remember better, and McGaugh believes the same thing happens in people. "Suppose I said to you, 'You know, I've watched your programs a lot over the years, and although it pains me to have to tell you this, I think you're one of worst people I've ever seen on … now don't take it, don't take it

personally,'" McGaugh says.

"So, my stress system would go into overdrive, no question," Stahl says.

"Even with my telling you that it's not true, there's nothing to keep you from blushing, from feeling warm all over," McGaugh points out. "That's the adrenaline. And I dare say that you're gonna remember my having said that long after you've forgotten the other details of our discussion here. I guarantee it."

McGaugh says that’s why we remember important and emotional events in our lives more than regular day-to-day experiences. The next step in his research was to see what would happen when adrenaline was blocked; he started experimenting with

propranolol.

"Propranolol sits on that nerve cell and blocks it, so that, think of this as being a key,