Unpredictable epileptic seizures can now be stopped in their tracks with a new approach that activates optical fibers implanted in the brain when a computer system detects a real-time seizure. More than 3 million Americans suffer from epilepsy, a condition of recurrent spontaneous seizures that occur unpredictably, and that often cause changes in consciousness and can preclude normal activities such as driving and working. Seizures cannot be controlled with existing drugs for as many as 40 percent of patients, and even in those whose seizures are well-controlled, the treatments can have major cognitive side effects. Now neuroscientists at the University of California, Irvine, have created a fiber optic method that holds promise of better treatment options for severe epileptic episodes. The hippocampus (background image) is a critical brain region in temporal lobe epilepsy. Krook-Magnuson et al report that on-demand optogenetics targeting specific cell populations in the hippocampus stops seizures (EEG traces in image) in a mouse model of temporal lobe epilepsy, demonstrating the feasibility of a spatially, temporally and cell-type specific treatment for this devastating disorder. Courtesy of Caren Armstrong. The on-demand optogenetic technique targets specific cell populations in the hippocampus — a critical brain region in temporal lobe epilepsy — to stop seizures in a mouse model. Ivan Soltesz and colleagues created an electroencephalograph (EEG) based computer system that activates hair-thin optical strands implanted in the brain when it detects a real-time seizure. These fibers subsequently “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. The researchers discovered that this process is able to arrest ongoing electrical seizure activity and reduce the incidence of severe tonic-clonic events — the type of generalized seizure (formerly known as grand mal) most commonly associated with epilepsy, which affects the entire brain. Ivan Soltesz, UC Irvine Chancellor’s Professor and chair of anatomy and neurobiology, has helped shed light on the inner workings of the human brain. His research offers hope to millions who suffer from epilepsy. Courtesy of Steve Zylius/University Communications. “This approach is useful for understanding how seizures occur and how they can be stopped experimentally,” said Soltesz, the Chancellor’s Professor and chair of anatomy and neurobiology at UC Irvine. “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.” Although the study has been carried out only in mice, Soltesz is confident that the work could lead to a better alternative to the currently available electrical stimulation devices. The study — supported by the National Institutes of Health, the Epilepsy Foundation and the George E. Hewitt Foundation for Medical Research — appeared in Nature Communications (doi: 10.1038/ncomms2376). For more information, visit: www.uci.edu