Deep brain stimulation prevents epileptic seizures in mouse model

February 19, 2021

Epileptic activity originating from one or more diseased brain regions in the temporal lobe is difficult to contain. Many patients with so-called temporal lobe epilepsy often do not respond to treatment with anti-epileptic drugs, and the affected brain areas must therefore be surgically removed. Unfortunately, this procedure only gives seizure freedom to about one third of patients, so the development of alternative therapeutic approaches is of great importance. Scientists led by neurobiologist Prof. Dr. Carola Haas, head of the research group at the Department of Neurosurgery at Medical Center - University of Freiburg and the BrainLinks-BrainTools research center, have investigated a new therapeutic approach to prevent epileptic seizures in temporal lobe epilepsy. They showed in mice that low-frequency stimulation of specific brain areas could completely stop epileptic activity. Instead of using electric current, the researchers stimulated the cells with light. To do this, they had previously introduced a light-sensitive molecule into the cells that allows particularly precise stimulation. They published the results in December 2020 in the scientific journal elife.

"As soon as we stimulated the brain region with a frequency of one hertz, the epileptic seizures disappeared. This effect was stable over several weeks," Haas says. Habituation, which can occur with drug therapy, did not take place. The brain region was stimulated for one hour daily.

Circuits and cells identified

In temporal lobe epilepsy, the hippocampus is often pathologically altered and usually represents the so-called focus of epileptic activity. Previous studies have used precise genetic labeling techniques to map the fiber system and its synaptic contacts between the temporal lobe and hippocampus, which are typically preserved in temporal lobe epilepsy. The researchers used this fiber system to manipulate hippocampal activity in a specific and temporally precise manner using light-dependent proteins. Measuring brain waves showed that rhythmic activation of the diseased hippocampus at a low frequency of one hertz suppressed epileptic activity and prevented it from spreading.

Haas and her colleagues demonstrated that the anti-epileptic effect is largely due to the repeated activation of surviving granule cells in the seizure focus. Single cell studies confirmed the assumption that the granule cells are less excitable due to the stimulation, making the epileptic seizure less likely to spread. "It's also possible that we have a widespread network effect because the stimulation can spread through the hippocampal circuitry," Haas said.

In the future, the team, along with the medical physics department at the Medical Center - University of Freiburg, would like to use magnetic resonance imaging to observe the entire brain during stimulation. This technique could be used to identify additional brain regions that are affected by the stimulation. Corresponding findings on these could provide information on how they are connected and what further consequences stimulation has.
-end-
Original title of study: Hippocampal low-frequency stimulation prevents seizure generation in a mouse model of mesial temporal lobe epilepsy.

University of Freiburg

Related Hippocampus Articles from Brightsurf:

Brain remapping dysfunction causes spatial memory impairment in Alzheimer's disease
A research group elucidated the brain circuit mechanism that cause of spatial memory impairment in Alzheimer's disease.In the future, improving brain remapping function may reverse spatial memory impairment in patients with Alzheimer's disease.

Impact of family income on learning in children shaped by hippocampus in brain
A new study by a team of researchers at the University of Toronto identifies the region of the brain's hippocampus that links low income with decreased memory and language ability in children.

Inhibitory interneurons in hippocampus excite the developing brain
A new study from the George Washington University, however, reports that in some critical structures of the developing brain, the inhibitory neurons cause excitation rather than suppression of brain activity.

A good blood supply is good for memory
Memory performance and other cognitive abilities benefit from a good blood supply to the brain.

Scientists identify circuit responsible for building memories during sleep
Neuroscientists at the University of Alberta have identified a mechanism that may help build memories during deep sleep, according to a new study.

Lack of oxygen doesn't kill infant brain cells, as previously thought
Research, conducted at OHSU and published in the Journal of Neuroscience, raises new concerns about the vulnerability of the preterm brain to hypoxia.

Schizophrenia: Adolescence is the game-changer
Schizophrenia may be related to the deletion syndrome. However, not everyone who has the syndrome necessarily develops psychotic symptoms.

How the olfactory brain affects memory
How sensory perception in the brain affects learning and memory processes is far from fully understood.

Penn researchers discover the source of new neurons in brain hippocampus
Researchers have shown, in mice, that one type of stem cell that makes adult neurons is the source of this lifetime stock of new cells in the hippocampus.

Scientists find first evidence for necessary role of the human hippocampus in planning
A team of scientists reports finding the first evidence that the human hippocampus is necessary for future planning.

Read More: Hippocampus News and Hippocampus Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.