October 09, 2018
For those who experience seizures, or know somebody who does, understanding them and being aware of the signs are a crucial aspect of living with epilepsy.
People who experience epileptic seizures often explain the episode to be similar to an earthquake: it starts slowly from within, eventually growing to a level out of their control. But the studies out of Jefferson provide data suggesting that seizures actually begin with a spike in inhibition, rendering patients confused, unable to form complete sentences among other things.
These neurons, which cause the rise in inhibitions that lower brain activity, may be to blame for the emergence of a seizure.
The research, published in the "Annals of Neurology," was led by Dr. Shennan Weiss, assistant professor of neurology and head of Thomas Jefferson Computational Epilepsy Laboratory, who believes the data could provide a shift in how medical professionals treat and prevent epileptic seizures. Per Jefferson’s release:
“Neurologists have long held the belief that seizures begin as an imbalance of excitatory and inhibitory neurons that lead to the over-excitation, but it had never been proven experimentally. For the past 20 years or so, researchers working with animals have observed that a burst of inhibition often precedes seizure onset. 'Since no one could observe the same in humans, many people assumed this observation was a quirk of drug-induced seizures in animals, and not applicable to humans,' said Dr. Weiss.”
Weiss and his team examined data gathered from neurosurgeon collaborators at Jefferson and the University of California at Los Angeles. In order to determine the exact location where a seizure begins, neurosurgeons would place electrodes in the brain before surgery. This allowed the team to catch 13 spontaneous seizures and measure impulses — or, “action potentials” — produced by excitatory and inhibitory neurons.
Weiss’s team found that many patients claim to experience an “aura” before the onset of a seizure, which could very well be the spike in inhibitory neurons found by his team. Further, the Jefferson doctor believes that patients experience some form of brain fog when the inhibitory neurons are activated at the onset of a seizure. About 10 seconds after the inhibition, over-excitation — which causes seizures — spreads over the brain.
Interestingly, Weiss believes this rise in inhibition may be the brain’s way of putting the brakes on that over-excitement in the brain. The only thing is, this may actually make things worse, kind of like when “you pull the brakes too hard on a bike and you fly over the handlebars,” according to Weiss.
All in all, this new research opens many avenues for understanding how seizures work as well as the best ways to treat and prevent them — which offers a measure of hope those who suffer from epileptic seizures.