Nav: Home

Epilepsy study links mossy brain cells to seizures and memory loss

February 15, 2018

A small group of cells in the brain can have a big effect on seizures and memory in a mouse model of epilepsy. According to a new study in Science, loss of mossy cells may contribute to convulsive seizures in temporal lobe epilepsy (TLE) as well as memory problems often experienced by people with the disease. The study was funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health.

"The role of mossy cells in epilepsy has been debated for decades. This study reveals how critical these cells are in the disease, and the findings suggest that preventing loss of mossy cells or finding ways to activate them may be potential therapeutic targets," said Vicky Whittemore, Ph.D., program director at NINDS.

Mossy cells, named for the dense moss-like protrusions that cover their surface, are located in the hippocampus, a brain area that is known to play key roles in memory. Loss of mossy cells is associated with TLE, but it is unknown what role that plays in the disease. Using state-of-the-art tools, Ivan Soltesz, Ph.D., professor of neurosurgery and neurosciences at Stanford University, Palo Alto, California, and his team were able to turn mossy cells on and off to track their effects in a mouse model of epilepsy.

"This study would not have been possible without the rapid advancement of technology, thanks in part to the BRAIN Initiative, which has encouraged scientists to develop innovative instruments and new ways to look at the brain," said Dr. Soltesz. "It's remarkable that we can manipulate specific brain cells in the hippocampus of a mouse. Using 21st century tools brings us closer than ever to unlocking the mysteries behind this debilitating disease."

In TLE, many seizures, known as focal seizures, originate in one part of the brain and are evident on electroencephalography (EEG) scans that show the brain's electrical activity. These seizures can result in symptoms such as twitching or a strange taste or smell, and many people with TLE might not be aware that these symptoms are seizures. Sometimes, focal seizures can spread throughout the entire brain becoming generalized, resulting in involuntary muscle spasms, or convulsions, that affect the limbs and other parts of the body as well as loss of consciousness.

When Dr. Soltesz' group detected focal seizures on the mice's EEG scans, they turned mossy cells on or off to see whether they had any effect on the seizures. The researchers found that turning on the cells prevented the focal seizures from transitioning into convulsive ones. When the mossy cells were turned off, however, convulsive seizures were more likely to occur. Mossy cells had only a minor effect on the occurrence of focal seizures.

"This was the first time we were able to show specifically that mossy cell activity can control convulsive seizures," said Anh Bui, an M.D., Ph.D. student at the University of California-Irvine, and first author of the paper. "These mice were missing most of their mossy cells, yet we were able to see effects just by manipulating the small number of surviving cells."

People with TLE often experience temporary changes in thinking and long-term problems with memory. Dr. Soltesz and his colleagues looked at the role of mossy cells in two specific types of memory: object recognition and spatial memory, which refers to identifying where objects are located and navigating around the environment. In these experiments, the mice were placed in a chamber with two identical items. The following day, one of the items was replaced with a different one (to test for object recognition) or moved to a different location (to test for spatial memory).

The epileptic mice had trouble with spatial memory tasks but their ability to recognize objects was unaffected. In addition, turning off mossy cells in healthy mice also led to problems with spatial memory in those animals. These findings suggest that a decrease in mossy cells may lead to convulsive seizures as well as memory deficits.

More research is needed to further understand the role of mossy cells in seizure progression as well as their effects early in the disease.
-end-
This work was supported by the NINDS (NS086429, NS074702, NS094668).

For more information: https://www.ninds.nih.gov/Disorders/All-Disorders/Epilepsy-Information-Page

References:

Bui AD et al. Dentate gyrus mossy cells control spontaneous convulsive seizures and spatial memory. Science. February 16, 2018.

The NINDS is the nation's leading funder of research on the brain and nervous system. The mission of NINDS is to seek fundamental knowledge about the brain and nervous system and to use that knowledge to reduce the burden of neurological disease.

About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit http://www.nih.gov.

NIH/National Institute of Neurological Disorders and Stroke

Related Epilepsy Articles:

Antibodies in the brain trigger epilepsy
Certain forms of epilepsy are accompanied by inflammation of important brain regions.
Breaching the brain's defense causes epilepsy
Epileptic seizures can happen to anyone. But how do they occur and what initiates such a rapid response?
Using connectomics to understand epilepsy
Abnormalities in structural brain networks and how brain regions communicate may underlie a variety of disorders, including epilepsy, which is one focus of a two-part Special Issue on the Brain Connectome in Brain Connectivity, a peer-reviewed journal from Mary Ann Liebert, Inc., publishers.
Epilepsy: Triangular relationship in the brain
When an epileptic seizure occurs in the brain, the nerve cells lose their usual pattern and fire in a very fast rhythm.
How concussions may lead to epilepsy
Researchers have identified a cellular response to repeated concussions that may contribute to seizures in mice like those observed following traumatic brain injury in humans.
Understanding epilepsy in pediatric tumors
A KAIST research team led by Professor Jeong Ho Lee of the Graduate School of Medical Science and Engineering has recently identified a neuronal BRAF somatic mutation that causes intrinsic epileptogenicity in pediatric brain tumors.
Can medical marijuana help treat intractable epilepsy?
A new British Journal of Clinical Pharmacology review examines the potential of medicinal cannabis -- or medical marijuana -- for helping patients with intractable epilepsy, in which seizures fail to come under control with standard anticonvulsant treatment.
Fertility rates no different for women with epilepsy
'Myth-busting' study among women with no history of infertility finds that those with epilepsy are just as likely to become pregnant as those without.
Do women with epilepsy have similar likelihood of pregnancy?
Women with epilepsy without a history of infertility or related disorders who wanted to become pregnant were about as likely as their peers without epilepsy to become pregnant.
Hope for new treatment of severe epilepsy
Researchers at Lund University in Sweden believe they have found a method that in the future could help people suffering from epilepsy so severe that all current treatment is ineffective.
More Epilepsy News and Epilepsy Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.