WALTHAM, Mass. - By playing video games, teenagers with epilepsy are making important contributions to science: they've taught researchers that certain brain waves may be the key to learning and remembering how to find our way from one place to another. The work - which has the potential to help us understand how memory works and ultimately point to cures for both epilepsy and memory disorders - is reported in the June 24 issue of the journal Nature.
A team of neuroscientists from Brandeis University and Children's Hospital, Boston, examined the electrical activity in the teens' brains as they maneuvered through virtual mazes. The researchers focused on slow, rhythmic waves of electrical activity known as theta oscillations, produced when groups of brain cells, or neurons, all fire at once. It has long been recognized that when some brain waves go awry, they can spur epileptic seizures; it now appears that theta oscillations, a special kind of brain wave, are also important for our ability to navigate through our surroundings.
Lead author Michael Kahana, Ph.D., says the Nature paper bridges the gap between scientists' understanding of theta's role in animals and its role in humans. "Hundreds of papers have linked theta oscillations to spatial learning in rats and other animals; our study is the first to seal the link between theta and spatial learning in humans," says Kahana, assistant professor of psychology and neuroscience at Brandeis.
Kahana and his co-authors - Joseph Madsen, M.D., a neurosurgeon at Children's Hospital, Boston; Robert Sekuler, Ph.D., the Louis and Frances Salvage Professor of Psychology at Brandeis; Jeremy Caplan, a doctoral student in neuroscience at Brandeis; and Matthew Kirschen, an undergraduate research assistant at Brandeis - were assisted by a cohort of epileptic teens who played video games in the name of science. The game, created by a 15-year-old high school student specifically for this research, put the teenagers in virtual environments resembling those found in popular video games. The researchers' video game first leads players through the mazes, and then leaves them to find their own way through a sometimes baffling set of twists and turns. The key to success in the game is remembering where youΜve been and how you got there.
The teen navigators suffered from very severe epilepsy, a disorder in which some brain waves go out of control. In their case, the epilepsy could not be adequately treated with medication; instead, neurosurgeons must locate and remove the part of their brain where the seizures originate. To find out precisely where this epileptic focus is without disturbing healthy parts of the brain that are important for memory, language, and other cognitive functions, surgeons monitor the electrical activity of the brain by placing wires directly on the brain's surface.
With careful attention to the teenagers' safety and clinical treatment, the researchers used these wires to watch the electrical signals of the brain's work while the teens worked their way through the mazes. They found that various parts of the brain produced telltale waves, like the ones produced in the brains of rats and other animals during similar tasks. The episodes of theta oscillations were most pronounced when the youths were wending their way through extremely difficult mazes.
"By playing video games today, these heroic teenagers are helping the kids of the future have happier, healthier, seizure-free lives," Sekuler says. "With more work, we may be able to understand why the brain's rhythmic activity sometimes spins out of control. Our long-range goal is developing a cure for epilepsy."
Normal brain waves occur at characteristic frequencies that underpin various brain functions. One well-known rhythm of about 10 cycles per second, the alpha wave, is associated with relaxation, while a slower wave of 4 to 7 cycles per second, the theta wave, seems to be important in spatial learning.
In epilepsy's four million American sufferers, brain waves turn into miniature electrical storms that sweep across the brain. People with mild epilepsy can be treated with medication, diminishing the risk of powerful and dangerous seizures. In more severe cases, the only option is surgery to root out the part of the brain where the most violent, seizure-inducing waves start. Frequently, these seizures start in a part of the brain called the temporal lobe, which also plays a key role in memory.
This might not be a coincidence, Kahana says, and further research could help understand both how the brain remembers and why it can become epileptic. The Brandeis and Children's Hospital researchers believe that to understand epilepsy, it is important to understand memory, and vice versa. This understanding could lead scientists to better treatments for epilepsy and memory disorders.
Madsen, a neurosurgeon at Children's Hospital with a special interest in the treatment of epilepsy, says the recognition of theta as a neural "signature" for certain kinds of memory should help neurosurgeons avoid inadvertently excising regions key to memory and other critical brain functions. "These findings may help to identify where memory functions are located in the brain and eventually assist in the treatment of epilepsy using surgery or other methods," he says.
The research was sponsored by the National Institutes of Health.
EDITORS: Video footage of the computer game and one of the young patients playing it are available to illustrate this story, as are still images depicting the computer game. See http://www.brandeis.edu/news/epimage.html for a preview of the still images. Also, one of the young patients who took part in the experiments is available to speak with the media about her experiences. Please contact Steve Bradt at (781) 736-4203 for more information.
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