THURSDAY, July 18, 2002 (HealthDayNews) -- Your brain isn't wrinkled because it's old. Instead, it's scrunched into the skull -- picture a winter coat jammed into a gym locker and you'll get the idea.
Now, researchers think they've discovered a protein that may be the reason the human brain is too big for its britches.
If they're right, researchers in Massachusetts may be closer to understanding how the human brain becomes much larger than in other animals, giving people the power to speak, read and plan.
"The vast difference in brain size between a human and, say, a dog makes us the most dangerous creatures on the planet," says Dr. James Grisolia, a neurologist with Scripps Mercy Hospital in San Diego.
The cerebral cortex, the large surface layer of the brain, is responsible for much of the human brain's unusual heft. The cortex also holds two-thirds of the brain's neurons.
"When we have more cortex, it enables us to process more information, and do things like speak and read," says Dr. Anjen Chenn, a research fellow at Beth Israel Deaconess Medical Center. "During evolution, the cerebral cortex has undergone a disproportionately large increase in size compared to the rest of the brain."
Chenn and a colleague studied cortex size by tinkering with a protein called beta catenin in mice. They report their findings in tomorrow's issue of Science.
When researchers made it easier for the protein to work properly, mice were born with larger cortexes, Chenn says. Some mice had cortexes with twice the surface area of normal mice.
Researchers speculate the beta catenin protein tells brain cells whether to continue dividing during embryonic development or to stop and become neurons.
It's not clear whether the brainy mice are little Einsteins. Chenn says he didn't study their intellect, and doubts they're much smarter than the average mouse.
"It's possible, but probably unlikely," he says. "The development of intelligence is probably more complicated than putting together a bigger brain. You have to get everything connected up together correctly."
The research gives scientists greater insight into how the human brain develops and may help doctors treat patients whose brains are too big or too small, Chenn says.
Grisolia adds that beta catenin isn't the only key to brain growth. However, it could be useful in a variety of treatments.
"Maybe adding catenin to retarded infants will improve their brain growth and make them smarter," he suggests. "Maybe it will help prevent atrophy of the brain in old age and keep away the ravages of Alzheimer's, or at least normal aging."
"The chances that beta catenin itself could be used as a treatment are small, but once we understand how it works, the avenues may open to devising drugs that increase its effects or stimulate its production within the brain cells," he says.
Chenn says he plans to continue studying mice with bigger brains.
"There's no way of studying brain development in a dish," he says. "Looking at animals is probably the best way of understanding what might go on in humans."
What To Do
Get facts about the cerebral cortex from About.com.
Learn about brain injuries from the Brain Injury Association USA.
