Mapping the Brain While Treating Epilepsy
Date: November 1, 2011
At a special Johns Hopkins unit, patients can be seen repeating such mundane tasks as moving an arm or naming an object. In this seemingly trivial way, they are helping neurologist Nathan Crone gather information that could prove critical to their own quality of life—as well as to gain insights that could eventually lead to enormous advances in neuroscience. That’s because these patients, who suffer from epileptic seizures, have had their brains wired with electrodes that are recording the data Crone needs to safely treat their seizures as well as map the human brain. “These patients,” he says, “are helping science, so that science can, in turn, help them.”
Often the only way to relieve a patient of severe seizures is to surgically remove a part of his or her brain. But which part? To figure that out, surgeons implant a grid of several dozen electrodes over the surface of the cortex in the patient’s brain. For the next week, the patient performs simple motor, speech and memory tasks while the electrodes record the corresponding electrical activity in the brain and any seizure-related activity. “We can now see in unprecedented resolution where the brain is and isn’t active during each task,” says Crone. He and colleagues use the data to hunt down the small section of the patient’s brain most responsible for seizures and least tied to function. At the end of the week, that section is removed in surgery.
But in thinking about all the data accumulating across many patients, Crone realized he had a unique opportunity to derive general insights into which parts of our brains control what—that is, to create a map of the brain keyed to specific functions. Such a map could prove vital to treating other neurological problems as well as to improving learning and possibly to controlling prosthetic limbs with thoughts. And the electrical patterns Crone studies are already providing clues to how the brain encodes information. “If we can learn which signals carry the most important information, we could do an even better job of minimizing impairment when we remove tissue,” he says. That’s one way science could pay the patients with epilepsy back for sharing a precious glimpse into the inner workings of their brains.
- Challenge: Surgically stop seizures and map brain function
- Approach: Record brain activity with implanted electrodes and correlate it to tasks
- Progress: Patients are being relieved of seizures with little impairment.; the map is under way