UC Irvine neuroscientists terminate epileptic seizures with implanted optical fibers
Irvine, CA--Researchers at the University of California, Irvine have invented a way to terminate epileptic seizures using optical fibers implanted in the brain.1 So far tried only in mice, the optogenetic technique relies on an electroencephalograph (EEG) and specialized software to locate the area in the temporal lobe of the brain that tends to undergo a seizure, and application of light through a subsequently implanted optical fiber to stop the seizure.
The amber (589 nm) light is delivered to a volume of tissue less than a tenth of a cubic millimeter in volume. Application of the light terminated 57% (+/-12%) of seizures within one second of switching the light on.
Turning on opsins
The effect of the light is to “turn on” specially expressed, light-sensitive proteins called opsins, which can either stimulate or inhibit specific neurons in select brain regions during seizures, depending on the type of opsin. By arresting ongoing electrical seizure activity, the procedure was able to reduce the incidence of severe “tonic-clonic” (formerly called "grand mal") events.
"This approach is useful for understanding how seizures occur and how they can be stopped experimentally,” says Ivan Soltesz, one of the UC Irvine researchers. “In addition, clinical efforts that affect a minimum number of cells and only at the time of a seizure may someday overcome many of the side effects and limitations of currently available treatment options.”
More than three million Americans suffer from epilepsy, a condition of recurrent spontaneous seizures that occur unpredictably, often cause changes in consciousness, and can preclude normal activities such as driving and working. In at least 40% of patients, seizures cannot be controlled with existing drugs, and even in those whose seizures are well controlled, the treatments can have major cognitive side effects.
Soltesz said the work could lead to a better alternative to the currently available electrical stimulation devices.
REFERENCE:
1. Esther Krook-Magnuson et al., Nature Communications (20113); doi:10.1038/ncomms2376