Word: mcgaugh
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...brain. Some of them put the senses on high alert, ready to deal with a threat. But these signals also tell the neurons that any memories recorded in the next few minutes need to be especially robust. One piece of evidence for this scenario: Lawrence Cahill, a colleague of McGaugh's at Irvine, showed subjects emotionally arousing film clips, simultaneously gauging the activity of their amygdalae using positron-emission tomography (PET) scans. Three weeks later, he gave the subjects a surprise memory quiz. The amount of amygdala activity predicted with great accuracy how well they remembered the film clips...
What happens biochemically, says McGaugh, is that when faced with an emotion-charged situation, such as a threat, our bodies release the stress hormones adrenaline and cortisol. Among other things, these signal the amygdala, a tiny, neuron-rich structure nestled inside the brain's medial temporal lobes, which responds by releasing another hormone, called norepinephrine. Norepinephrine does two important things. First, it kicks the body's autonomic nervous system into overdrive: the heart beats faster, respiration quickens, and the muscles tense in anticipation of a burst of physical exertion...
This is an oversimplification, of course. Other neurotransmitters, and even plain glucose--the sugar the brain uses for energy--may also play a part. And then there's the peculiar case of a woman who contacted McGaugh because she remembers absolutely everything. The stress-hormone model does not appear to apply in her case. Says McGaugh: "At one point I asked if she knew who Bing Crosby was. She's 40, so Bing Crosby doesn't loom large in her life, but she knew he died on a golf course in Spain, and she gave me the date, just like...
...someone a shot of adrenaline, and memory temporarily improves. But it also drives up the heart rate, so it could be dangerous for the elderly. Other memory enhancers, like Ritalin or amphetamines, used by college students to cram for exams, are highly addictive. And some of the experimental drugs McGaugh is testing in rats can cause seizures. Unfortunately, he says, for people with truly serious memory problems, "existing drugs are not yet powerful enough or nice enough...
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...