We all suspect we're unique, and methods for identifying individuals, whether by examining fingerprints or strands of DNA, confirm this conviction. A recent study shows that each person's mind also exhibits a distinct pattern that could be used as a distinguishing feature with near-perfect accuracy.

The researchers, led by Emily Finn of Yale University, relied on functional connectivity MRI (fcMRI) to examine brain activity in 126 healthy young adults. A “connectivity profile” was then created for each subject based on an estimate of the strength of connections between every pair of nodes in a network of 268, representing various brain regions. These fingerprintlike profiles identified participants with 94 percent accuracy.

The team then looked at groups of nodes that correspond with networks dedicated to visual, motor or other tasks to see if some networks contributed more to individuality than others. The frontoparietal network, involved in focusing our attention, performed best, allowing the group to identify individuals with 99 percent accuracy. This recently evolved network is thought to be sensitive to one's experience, whereas sensory and motor networks are considered more hardwired. “We all can see the rock falling and get out of the way,” says cognitive neuroscientist Michael S. Gazzaniga of the University of California, Santa Barbara. “But some of us are better at figuring out why it fell in the first place.”

The study authors do not support using these techniques to identify people. “We don't need to put people in a scanner to know who they are,” Finn says. But the finding, published last fall in Nature Neuroscience, does suggest new clinical applications for fcMRI. “It could be a fingerprint for mental health,” says neuroimaging expert Cameron Craddock of the Nathan S. Kline Institute for Psychiatric Research. Finn notes that her team has already started working with data from adolescents at high risk for schizophrenia to see if the scans can be used to predict who will go on to acquire the disorder.