Our Brains Have 'Fingerprints' — And We Can Find Them Fast

We think of fingerprints as being something each of us carries around on the terminal knuckle of all our fingers, unchanging and unique from everybody else's. That might be true for our digits, but new research suggests that our brains have "fingerprints" too, and that we can find them quickly.

Using an MRI machine, neuroscientists can create what amounts to a map of your brain, called a "functional brain connectome." The human brain is a little like a country with different regions in it — one region called short-term memory, another hearing, another called hand movement. These brain regions are called cortical areas, and our brain has 180 of them, and they're connected by these little neural fibers that act as highways. The connectomes are based on the activity the person is doing and what parts of the brain this activity needs to use.

In 2015, a Yale University study found that no two brain connectomes are the same — that when given MRI images of the same several brains over the course of a few days, the connectivity "fingerprint" of the organ could help scientists match up the brain with the study participant with around 95 percent accuracy.

In a new study, scientists examined how long it actually took to capture a snapshot of a person's brain fingerprint. In the past, MRI images were captured over the course of several minutes, but the research team wondered if they could be taken in a shorter time.

"Until now, neuroscientists have identified brain fingerprints using two MRI scans taken over a fairly long period. But do the fingerprints actually appear after just five seconds, for example or do they need longer? And what if fingerprints of different brain areas appeared at different moments in time? Nobody knew the answer. So, we tested different time scales to see what would happen," said Enrico Amico, a scientist and SNSF Ambizione Fellow at EPFL's Medical Image Processing Laboratory and the EPFL Center for Neuroprosthetics, in a press release.

Amico and his colleagues found that one minute and 40 seconds was long enough to capture a brain fingerprint, and that an individual's unique brain map could begin identifying sensory information first (like eye movement), before the areas of more cognitive functions. Their research appeared in the journal Science Advances in October 2021.

The research team plans to compare the brain fingerprints of patients with Alzheimer's to those of healthy people. "Based on my initial findings, it seems that the features that make a brain fingerprint unique steadily disappear as the disease progresses. It gets harder to identify people based on their connectomes. It's as if a person with Alzheimer's loses his or her brain identity," said Amico.

Knowing this could mean earlier detection of neurological conditions like autism, stroke or dementia that might cause a brain fingerprint to disappear.