In a lot of ways, a brain is a brain is a brain. The motor cortex gets you moving, the temporal lobe helps you communicate, the amygdala is your emotional center. But zoom in on the complex interactions between those parts and something remarkable emerges: you.
"We are all unique in our wiring patterns and those come about as a result of our genes and our experiences working together," said David Eagleman, a neuroscientist at the Baylor College of Medicine.
A study out this week in the journal Nature Neuroscience puts this uniqueness into stark relief. Researchers at Yale University showed that the brain has such a particular profile that they could identify individuals by their brain scans alone.
The study used fMRI (functional magnetic resonance imaging), which plots brain activity and the connections between different active regions.
"In fact, it turns out that the ebb and flow of brain activity is like a fingerprint: Each person has their own signature pattern," wrote lead author Emily Finn, a PhD student at Yale. "Using only their connectivity profiles, we could identify individuals from a group."
Finn and her team were even able to use these neural portraits to reliably predict fluid intelligence, a measure of reasoning ability.
The most unique connection patterns were between the prefrontal and parietal lobes, which are critical for higher order cognitive functions like attention, language and decision making. This makes sense, since other regions, such as the primary visual cortex or the primary motor cortex, control functions that are mostly similar in healthy people. (Though there were connectivity variations there, too.)
"People think differently, therefore you see these different profiles," Finn told CBS News.
What we don't know -- yet -- is whether we think differently because our brains are wired differently or if our brains are wired differently because of the way we think.
It's a distinctly human conundrum.
"Other animals are more hardwired. A baby zebra can run after just a few minutes of dropping out of its mother's womb. Human babies cannot do that," Eagleman said. "Human brains drop into the world much more unfinished than other animals'. It seems like a disadvantage, but in fact it is the thing that allows us to flexibly absorb the environment and culture that we drop into."
As we develop and learn, our brains grow and make new neuronal connections. And even as our brains mold and change, Finn's research shows, there is a signature that makes each person's lump of gray matter distinctly his own.
Eagleman explores the relationship between the brain and the self in his new book, "The Brain," and a six-part PBS series starting Wednesday by the same name.
"Each of us is on our own trajectory -- steered by our genes and our experiences -- and as a result every brain has a different internal life. Brains are as unique as snowflakes," he says, in the book and in the show.
"As your trillions of new connections continually form and re-form, the distinctive pattern means that no one like you has ever existed, or will ever exist again."