It isn't uncommon for people to pass for ages much older or younger than their years, but researchers have now found that this feature doesn't apply to our brains. The findings reported online on August 16 in Current Biology, a Cell Press publication, show that sophisticated brain scans can be used to accurately predict age, give or take a year.

It's a "carnival trick" that may have deeper implications for both brain science and medicine.

"We have uncovered a 'developmental clock' of sorts within the brain -- a biological signature of maturation that captures age differences quite well, regardless of other kinds of differences that exist across individuals," says Timothy Brown of the University of California, San Diego School of Medicine.

Together with UCSD's Anders Dale and Terry Jernigan and researchers from nine other universities, Brown used structural magnetic resonance imaging (MRI) to scan the brains of 885 people ranging in age from 3 to 20. Those brain scans were used to identify 231 biomarkers of brain anatomy that, when combined, could assess an individual's age with more than 92 percent accuracy. That's beyond what's been possible with any other biological measure, the researchers say.

While others had looked at some of the same brain biomarkers in the past one by one, the key was finding a way to combine them to capture the multidimensional nature of brain anatomy and characteristic patterns of developmental change with age. Brown says that they are excited to further explore the new approach and its potential for use in the clinic.

"The fact that we found a collection of brain measures that so accurately captures a person's chronological age means that brain development, or at least certain anatomical aspects of it, is more tightly controlled than we knew previously," Brown says. "The regularity in this maturity metric among typically developing children suggests that it might be sensitive to detecting abnormality as well."

It's not yet clear how these anatomical changes in the brain will relate to maturity in terms of human behavior, which we all know isn't necessarily reflected by our chronological age.

"The anatomy and physiology of these dynamic, interacting neural systems, which we can probe in different ways with MRI scans, have to account for the changes we all observe in human psychological development," Brown says. "We're still figuring out exactly how."