Inhibiting the communication between nerve cells located on different sides of the brain can prevent epilepsy seizures from spreading, a mouse study shows.
The study “Dynamic interaction of local and transhemispheric networks is necessary for progressive intensification of hippocampal seizures” was published in the journal Scientific Reports.
Led by researchers at Lund University in Sweden, the study provides new insights about how brain nerve cells’ networks function during epileptic seizures. This finding may pave the way for development of new therapeutic strategies that can help people with different types of epilepsy, including Dravet syndrome, who do not respond to available drugs.
“In mice studies, we succeeded in reducing seizure activity by intervening in an area of the brain that is not the focus of the epileptic seizures, but is directly connected to it through a network of neurons,” Mérab Kokaia, professor and director of the Epilepsy Centre at Lund University, said in a press release. Kokaia was senior author of the study. “If we get the same result in further, long-term studies, it could pave the way for treatment of severe epilepsy,” he added.
The team used two specific methods, called optogenetics and chemogenetics, to better control brain cells’ activity while allowing a detailed understanding of their communication networks.
Mice brain cells were changed to be responsive to light (optogenetic), which means that instead of electrical stimuli researchers could use light to activate the cells and trigger epileptic-like brain activity. Brain cells also were transformed to have one specific cellular receptor that could be activated only by the presence of a man-made chemical compound (chemogenetics), enabling them to reduce activity in the specific areas and nerve cells involved in an epileptic seizure. Meanwhile, other parts and cells in the body remain unaffected, lowering potential side-effects.
The team used these approaches in mice to trigger epileptic-like activity in a small group of cells located in the hippocampus, a brain region important for memory and learning and that, in the most severe cases, where epileptic seizures start.
However, when the same method was applied to cells located in the exact opposite hippocampal site of the seizure focus, the hyperactivated signals were unable to spread and the seizure ceased.
This finding shows that epileptic seizures require active brain cell communication networks between the two hemispheres of the brain. But it also revealed a new potential strategy that could be used to prevent seizures.
“This is the first study in which we succeeded in reducing the epileptic activity in one area of the brain by using chemogenetics to affect another area, not the seizure focus,” Kokaia said. “This opens up the possibility of treating epilepsy in areas of the brain that cannot be surgically removed or treated directly.”