Anti-epileptic drugs (AEDs) are the first-line treatment for epilepsy, but approximately one third of people fail to achieve seizure control with these drugs and must seek alternative therapies. In specially considered cases, surgery is performed to remove the affected brain tissue.

The reason why some people don't respond to AEDs is not entirely understood; but it has been the subject of research for many years. Scientists have always relied upon mouse models to study the activity of the epileptic brain, but there is a limit to the accuracy of this when it is applied to humans.

Recently, however, Dr Mark Cunningham and colleagues from the University of Newcastle, successfully recorded epileptic activity in human brain tissue that had been removed from patients during epilepsy surgery.

In order for the team to get a true picture of the tissue's electrical activity, it was important that it behaved exactly as it had before removal. To achieve this, the tissue specimens were kept in a special environment that mimicked the living brain.

The researchers first recorded electrical signals from the neurons within the tissue. When they compared these to normal brain activity, they noticed that the epileptic tissue displayed a distinct underlying brainwave. This type of brainwave is also found in intact human epileptic brains, and is believed to be a precursor to seizure activity. This finding suggests that the extracted brain tissue was behaving as it had before removal.

The scientists then tried to discover what was causing this brainwave, by examining individual and groups of neurons within the tissue. Interestingly, they noticed that the activity was controlled by direct electrical connections between the neurons, not by chemical signals as they had thought.

Conventional AEDs exert their effects at synapses (gateways of chemical communication between neurons). However, if the electrical activity leading to a seizure is unrelated to these synapses, AEDs will be useless at curbing it and preventing a seizure.

These results are very exciting, because they could explain why certain people are unresponsive to AEDs. They could also open avenues for the development of alternative epilepsy treatments.

Dr Cunningham has been quoted:

"These findings have massively increased our understanding of epilepsy and offer real hope in terms of finding new ways of tackling the disease.

"The next step is to understand what it is that triggers the transition between the underlying epileptic state of the brain cells and the fast oscillations that are responsible for causing a seizure."

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