On a quest to map the brain’s hidden territory
Superscanner could help illuminate the functions behind thoughts, sensations
The black-and-white brain scans that have become a routine part of medicine reveal a curved gray structure folded around large lakes of white — a map that helps doctors diagnose, treat, and understand disease. But to some scientists, these images are crude and incomplete, akin to medieval maps of the world in which unexplored regions were filled in with sea monsters or dragons.
“It’s like there’s a continent there, and we are nibbling along the shores,’’ said Dr. Van Wedeen, a physicist and radiologist at the Martinos Center for Biomedical Imaging at Massachusetts General Hospital. He is helping to lead an effort to develop a superscanner that can reveal that unknown territory and provide new insight into the brain.
On a recent morning, Wedeen pulled up images created with the new technology, in which the lakes of white were crisscrossed by colorful, ropy bundles of fibers, revealing an elegant, three-dimensional architecture. Looking more like art than anatomy, these strands form the connections in the brain — the “connectome.’’ They are neural highways crucial for brain function, including thoughts, movements, and sensations.
“This isn’t just statistical stuff, or mush, or steel wool, or chaotic spaghetti,’’ Wedeen said. “This is as important a structure as you’re ever going to meet, and this thing had to be designed by evolution.’’
With Dr. Bruce Rosen, director of the Martinos Center, and Arthur Toga at the University of California Los Angeles, Wedeen is developing the next generation of an MRI scanner to perform diffusion spectrum imaging, which should be faster and produce higher-resolution pictures than current machines.
The technology maps the movement of water in cells to trace the links that stretch across the brain. The team was awarded an $8.5 million, three-year grant last month by the National Institutes of Health and is working with
The collaboration is one branch of the Human Connectome Project, a coordinated federal effort that aims to catalog and understand the structure and function of connections in a normal adult brain.
As the genome is a fundamental map of genes and DNA structure, “the connectome is the fundamental map of how the brain is wired and how those parts work together,’’ Rosen said.
Researchers from Washington University in St. Louis and the University of Minnesota will map the connections in the brains of 1,200 healthy adults and combine that information with genetic and behavioral data. Eventually, by making comparisons with brains of people with psychiatric diseases and developmental disorders, scientists hope to begin to unravel how differences in the wiring and connections of the brain might underlie behavior or disease.
“Right now in the human brain . . . we have very little information about connectivity,’’ said Michael Huerta, director of the National Institutes of Health Connectome Initiative.
“People have had hypotheses for this for a long time, but we haven’t had the data to really work on it. Schizophrenia is thought by some people to be disrupted connectivity; autism is increasingly thought of as perhaps aberrant connectivity. . . . What we’re looking to do with the connectome project is fill in this crucial, but missing, class of data.’’
Already, doctors envision a use for the technology.
Dr. P. Ellen Grant, director of the Fetal-Neonatal Neuroimaging and Developmental Science Center at Children’s Hospital Boston, said such technology could be important in understanding damage to young brains.
“You can look at what systems are being altered or injured by disease and how the connections may be altered from the very beginning,’’ Grant said.
Ultimately, she said, it may be possible to scan a premature baby’s brain, to see whether connections that will be fundamental to language or movement appear to be abnormal. If they are, it could open the door to providing therapies that could strengthen or foster those connections. That could give doctors the ability to tailor therapy when the developing brain is still quite dynamic, and well before there may be clear signs of cognitive problems.
Once a connectome scanner is developed, Grant hopes to put one near the neonatal and pediatric intensive care units.
But what scientists and clinicians will find when they can peer into the brain with such detail is not yet known.
“There’s excellent evidence we’ll see things we can’t see today,’’ Rosen said. “The more interesting question is what exactly that extra resolution and detail is going to mean — is that going to capture the keys to understanding the variance between people and understanding the variance in behavior?’’
Carolyn Y. Johnson can be reached at firstname.lastname@example.org.