Researchers at the University of California, San Diego School of Medicine have discovered that convulsive seizures in a form of severe epilepsy are generated, not on the brain's surface as expected, but from within the memory-forming hippocampus.
The scientists hope that their findings - based on a mouse model of severe epilepsy - may someday pave the way for improved treatments of childhood epilepsy, which affects more than two percent of children worldwide. Their study will be published online by the Proceedings of the National Academy of Science ( PNAS ) the week of March 16.
"A parent of an epileptic child will tell you that they think their child is going to die during their attacks," said senior author Joseph Gleeson, MD, director of the Neurogenetics Laboratory at the UC San Diego School of Medicine, professor in the department of neurosciences and Howard Hughes Medical Institute Investigator. "Parents of children with epilepsy, especially the most severe types of epilepsy, are desperate for a deeper understanding of the causes of the problems and for the development of new treatments."
One of the major causes of epilepsy in children is an alteration in the development of the cerebral cortex. The cerebral cortex is the main folded part of the brain, containing a large percentage of brain cells, and is integral to purposeful actions and thoughts. However, this complex structure is subject to all kinds of defects in development, many of them due to defective genes and many associated with epilepsy.
Cortical dysplasia, meaning disordered development of the cerebral cortex, is identified in 25 to 40 percent of children with the most severe and difficult-to-treat forms of epilepsy. These children often come to the attention of specialists due to stagnation in the acquisition of language and balance skills and accompanying epilepsy. The symptoms displayed by these children can range from very subtle - such as small muscle jerks or eyelid fluttering - to dramatic whole body, tonic-clonic spasms (a series of contractions and relaxations of the muscle) that can affect basic bodily function.