Hidden Valley Road - Inside the Mind of an American Family - Robert Kolker Page 0,90

a middle ground between nature and nurture by suggesting that certain genetic traits directly compromised the brain’s sensory and information-processing functions, making the brain especially vulnerable to any number of environmental triggers. To these researchers, those triggers—anything from everyday heartbreak, to chronic poverty, to traumatic child abuse—didn’t cause schizophrenia as much as provide “an opportunity for vulnerability to germinate into disorder.” And that vulnerability, many thought, was really an issue with “sensory gating,” or the brain’s ability (or inability) to correctly process incoming information. A sensory gating disorder was the most common explanation for the schizophrenia experienced by John Nash—the Nobel Laureate mathematician depicted in A Beautiful Mind—who was able to detect patterns no one else could, and yet also was prone to delusions and visions of beings who were out to get him. Both of those aspects of Nash’s personality were said to be products of the same hypersensitivity.

Neurons talk to one another through brain synapses, the junctions between nerve cells that are essential for sending messages through the central nervous system. Many researchers came to suspect that the John Nashes of the world weren’t able to prune their synapses in the same way as most people.* Some people with schizophrenia, they thought, might become sensitive to distracting sounds and feel flooded by too much information—the way it sometimes seemed Peter Galvin felt, or Daniel Paul Schreber had back in 1894. Others might become hyper-reactive, guarded, even paranoid—like Donald Galvin, mysteriously inspired to move all the furniture out of the house on Hidden Valley Road. Still others might be unable to pick and choose what to focus on with any reliability and might become delusional—seeing hallucinations and hearing voices, like Jim Galvin.

Sensory gating was just a theory. But once Freedman came to the subject, in 1978, as a researcher at the University of Colorado Medical Center in Denver, he started to develop a deceptively simple method for measuring sensory gating—and, by extension, indirectly measuring the vulnerability of a brain to schizophrenia. Freedman realized that the other researchers who were studying sensory gating—measuring their test subjects’ reactions to various lights and sounds and such—were skipping right past an important part of the process. As a neurophysiologist, Freedman understood physical reflexes and their peculiar, even counterintuitive relationship with the brain. He knew there were neurons—brain cells—that ordered you to move your muscles, but also neurons that inhibited the movement of those same muscles. In order to walk, for example, your central nervous system needs both kinds of neurons, for action and inhibition. Otherwise, everyone would be falling down all over the place. Why wouldn’t it be the same, Freedman wondered, for thinking?

What if the problem with schizophrenia patients wasn’t that they lacked the ability to respond to so much stimuli, but that they lacked the ability not to? What if their brains weren’t overloaded, but lacked inhibition—forced to reckon with everything that was coming their way, every second of every day?

In 1979, working at his lab in Denver, a little more than an hour’s drive from the Galvin family’s home on Hidden Valley Road, Freedman developed a method of measuring inhibition that was painless for the patients: A small electrode was placed on the test subject’s scalp, and that electrode measured electrical activity in the form of waves. Bigger waves meant the brain was working harder to process information; smaller waves meant the brain was doing less. Freedman devised an experiment. He measured his test subjects’ reactions when they heard the same exact noise—a click—played twice, with just a short interval between them, usually half a second.

Any so-called “normal” brain, a brain without schizophrenia, recorded a large brain wave reacting to the first click, followed by a smaller wave reacting to the second click. The normal brain learns from what it perceives. It doesn’t have to start from zero if it hears the same thing twice. People with schizophrenia, however, couldn’t manage that. In test after test, conducted at Freedman’s lab in Denver, their brains showed two waves of equal size for the two clicks. It was as if they had to react all over again to the second click—even though they had just heard the same click a fraction of a second earlier.

The double-click test was not testing for schizophrenia itself. It was testing sensory gating, which was one potential aspect of schizophrenia. What