Our Serotonin, Our Selves? - Page 6


As I watch her work, it's evident that she's an artist at brain slicing. After the section has been cut, she deftly places it between two glass slides, and then pats the outside of the glass with her fingers. I realize she's defrosting it with the repeated, firm taps of her fingers. The hair-thin section within the glass quickly takes on a beautiful glow, like a hologram.

Manuela explains that the brains are collected at autopsy and "flash frozen" in Freon at minus 20 degrees centigrade. Then they're stored at minus 80 degrees centigrade, sometimes for years, until they're sectioned. She tells me that when they're collected, the brains are divided into right and left hemispheres, and then a hemisphere is cut into 10 or 12 blocks. Manuela produces 160 sections from each block.

Once securely placed on the glass, the samples are frozen until the day of the experiment, when they're brought to room temperature and dried under vacuum. Each brain section goes through 20 different treatments—exposure to radioactive chemicals, immersion in liquids—repeatedly. Each step takes from a few minutes to a few hours. At the end, the slides are placed next to X-ray film and exposed in the dark for varying times, depending on the experiment. The presence of radioactivity in the molecules creates images on the film, and the exposed film reveals the different receptors that tell the story of the serotonin, allowing the scientists to measure the amounts present in the brains of those who committed suicide and those who didn't.

Many things about the lab surprise me. I'm amazed at how "low-tech" the equipment is. Other than the computer equipment, it reminds me of a larger, more deluxe version of my high school lab. There's an organized trail of beakers, vials, tubes, and metal trays; lots of microscopes; and numerous technicians in white coats. It all looks like it could be from the '50s. I was expecting to see huge computers and whirring brain-imaging machines.

For two decades, Mann and Arango have been the principal investigators at this center, the only federally funded program to research suicidal behavior across the life cycle. "We've learned from earlier work that alteration in the serotonin system, which is under significant genetic control, may be a predictor for suicidal behavior," Mann says. Their inquiries have led them to zero in on the prefrontal cortex, the area of the brain that lies behind the forehead, which is the source of the brain's "executive functions," including controlling impulsivity. This characteristic has long been implicated with suicide. While some people anticipate their suicides—making elaborate plans, leaving detailed notes, laying out insurance papers—many others do it as a spontaneous act, the product of a temporarily imbalanced mind. "Carefully planned acts of suicide are as rare as carefully planned acts of homicide," wrote suicide researcher Erwin Stengel in 1964.

Studies have shown that people under extreme emotional stress are prone to extreme cognitive distortions. "Most people," Stengel noted, "in committing a suicidal act, are just as muddled as when they do anything important under emotional stress." Even a day later, the distortions may lift, and someone who almost committed suicide may see life and its daily problems in a far different light. Many survivors of a suicide attempt have attested to how fortunate they feel that they didn't die, and have said that what led them to hurt themselves was a temporary loss of control or balance.

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