BRAIN

In the hallowed tradition of B. F. Skinner, psychiatrist Jay Giedd has turned family life into a living laboratory: every three months, he gives his daughter a brain scan.

When Alexandra was born in 1993, Giedd was already immersed in a study of brain growth in children. He knew that his little subject could provide him with material impossible to come by from scanning a child every few years.

"Let's wait until she wants to," urged Gwendolyn Giedd, mother of "Sasha," as she's known. It didn't take long: Sasha was three when she said, "I want a brain picture."

So every three months, Sasha and her dad head to his lab at the National Institute of Mental Health in Bethesda, Maryland, where she crawls into the MRI scanner with her teddy bear. She's became so comfortable with the procedure that she even falls asleep in the "noise machine," as she calls it. Now five, she wants to be a scientist.

Giedd and his colleagues have scanned the brains of more than 800 children, many of them with schizophrenia or attention deficit hyperactivity disorder (ADHD). About a third of the kids are, like Sasha, behaviorally normal.

They've found that the right side of the brain in boys with ADHD is 8% smaller than that of normal boys' brains. And in children plagued by phantom voices or images, the brain's ventricles grow larger than normal between the 14th and 17th year. At the same time, the thalamus, a key relay center, shrinks.

As the youngest brain in the study, Sasha's scans are telling. A sneak peek at the blinded data last month revealed that her corpus callosum--the nerve bundle that allows the two hemispheres to communicate--has already increased over 15% in size. Her white matter, which supports important cortical connections, has grown by 20%.

"You can find out a lot more about the developing brain when you study the same person over time," says the proud father. "Statistics tell us we need thousands of kids to see a developmental curve, but this is the only way we can capture the subtle twists and turns."