In epilepsy, the neurons misfire and create abnormal electrical activity
Experts believe they have uncovered the root cause of "stubborn" epilepsy that fails to respond to drug treatment.
Tests on patients' brain tissue revealed some seizures are caused by electrical connections between nerve cells rather than chemical ones.
This faulty wiring would explain why traditional drugs are useless and why some patients have to resort to surgery, say the UK researchers.
Their work appears in Proceedings of the National Academy of Sciences.
Dr Mark Cunningham and his team at Newcastle University hope the findings will open the door to new treatments for the condition which affects an estimated 45 million people worldwide.
In almost 30% of epilepsy patients drug treatment fails and some resort to surgery to remove the brain tissue responsible for the condition.
The researchers took brain tissue removed from people with epilepsy and in the lab were able to coax it to behave as if it was still part of the living brain.
They were then able to record electrical signals from individual neurons and networks of neurons in the samples.
Comparing this with normal brain tissue activity, they managed to record an underlying 'noise' - a particular type of brain wave, or oscillation, which occurs in the intact epileptic human brain and which scientists believe is a precursor to an epileptic seizure.
They then found that rather than being controlled by chemical signals which most conventional anti-epileptic drugs target, this oscillation relies on direct electrical connections.
Dr Cunningham said the next step would be 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.
Simon Wigglesworth of Epilepsy Action said: "This is exciting news for people whose epilepsy cannot be controlled by medication and an important development in our understanding of the condition.
"Currently, there is no treatment to cure epilepsy other than surgery, which at the moment is only effective for small numbers.
"We hope that this research will move us closer to effective treatment".
A spokeswoman for Epilepsy Research UK described the research as "very promising".