Uncovering the Secret Language of the Brain
By Cary Estes
Imagine you are given a book that contains answers to some of life’s greatest mysteries. You have an intimate knowledge of the ink used in printing the book. You understand the composition of the paper and the molecular structure of the cover. Then you sit down to read, and you find out the book is written in an unknown alphabet. You have a few clues, but the only way to decipher the message is through sheer trial and error.
This is roughly the situation in which Timothy Gawne, Ph.D., finds himself. A neuroscientist with the UAB Department of Vision Sciences, Gawne has spent nearly 20 years struggling to crack the brain’s neural code—the puzzling pattern of communication between neurons that allows our skull-bound brains to interpret and interact with the larger world.
A breakthrough in the field could revolutionize robotics, computing, and the treatment of neurological disorders. But first, scientists have to work out how the mind talks to itself.
“We know about neurons and what sort of molecules they’re made out of and enzymes and neural transmitters and genes and all these little pieces,” Gawne says. “But we don’t know how the whole system functions. We don’t know the larger meaning of the pattern of what’s being said.”
Talk, Talk, Talk
Just as our genetic code is communicated by DNA and RNA, the neural code is transmitted from brain cell to brain cell through electrical surges known as action potentials. Sensory inputs such as sights, sounds, and smells travel through a bewildering maze of linked neurons as they move from the body surface to the heart of the brain, but the process remains a mystery.
The problem, Gawne says, is that the brain is an amazingly complex mechanism. “In the middle of the brain, where I study things, each neuron will typically talk to a thousand other neurons,” says Gawne. “It’s hard enough to trace the signal to the other neurons, because they’re spread out through the brain. But even if you could, each of those neurons is talking to a thousand more. So the signal disappears into this vast, complex system.”
Gawne uses high-powered computing techniques to make educated guesses about the correct combination of signal pathways. Then he tests these hypotheses against computer models and human experiments in visual perception to see if they are consistent.
“It’s sort of like a detective story,” Gawne says. “You get some data, you make a guess, and then you see where that guess leads you. Ultimately, if we can inject signals into the brain with electrodes, and they have the effect the model says they should—the subjects see what we think they should see—that’s success.”
Waiting for Eureka
Cracking the neural code would be even more significant than our recent success in sequencing the human genome, Gawne argues. “In many ways, it would be the single greatest advance in all of scientific history. If we really knew what was important in brain cells communicating to each other, then we would know exactly what to target in curing disease. We wouldn’t have to continue trying to randomly guess a 20-digit combination. We could just dial the number.”
Gawne is confident that the neural code eventually will be cracked. When that will happen, however, is anyone’s guess. “The amount we know now about the brain compared to 20 years ago is stunning,” he says. “But as far as the keystone advance, I think it’s going to be all or nothing. And it may be next year or it may be 20 years before we get the big picture.”