How brain injury leads to seizures, memory problems

Oct 18, 2006

In a finding that may provide a scientific basis for eventual treatment, neurology researchers have shown that traumatic brain injury reduces the level of a protein that helps keep brain activity in balance. The resulting abnormal activity, in turn, is thought to be an underlying reason for seizures and memory defects experienced by people who have suffered a traumatic brain injury (TBI).

"A traumatic brain injury occurs to someone in the United States every 23 seconds," said study team leader Akiva S. Cohen, Ph.D., of The Children's Hospital of Philadelphia, adding that, "TBI is the leading cause of death among children and young adults in this country. There are no cures known for traumatic brain injury. Our hope is that our research may contribute to potential therapies for TBI patients."

Transportation accidents such as car crashes are responsible for the majority of TBIs in people under age 75. According to the National Institutes of Health, over 5 million Americans currently have permanent disabilities resulting from TBIs.

The study, which was done in animals, appears in the journal Neurobiology of Disease, published online on Oct. 10.

Using mice, the researchers showed for the first time that TBI reduces the levels of a protein called potassium-chloride co-transporter 2 (KCC2) within a portion of the brain called the dentate gyrus. The dentate gyrus controls overactivity from reaching seizure-prone brain cells further along the circuit.

The dentate gyrus is a gatekeeper in maintaining a balance between two systems of neurotransmitters in the brain: the glutamate system and the gamma-aminobutyric acid system, abbreviated GABA(A). Glutamate stimulates neurons to fire, while GABA(A) inhibits that activity. "When lower levels of the KCC2 transporter weaken the dentate gyrus's ability to act as a gatekeeper," said Dr. Cohen, "neurons become more excitable, and seizures can occur."

In addition to its role in inhibiting seizures, the dentate gyrus is also believed to be important in memory formation. Therefore, said Dr. Cohen, "Interfering with normal function in the dentate gyrus may impair memory formation--especially antegrade memory, the ability to learn new things." Epileptic seizures and impaired memory are two of the disabilities caused by TBI.

Further animal studies, said Dr. Cohen, will investigate whether supplying KCC2 directly to the dentate gyrus will restore normal functioning in that structure, and whether it may improve symptoms in brain-injured mice. If this proves to be the case, the protein may someday be used as a medical treatment for patients with TBI.

Source: Children's Hospital of Philadelphia

Explore further: Global Ebola toll rises to 5,689: WHO

add to favorites email to friend print save as pdf

Related Stories

Increased brain protein levels linked to Alzheimer's

Sep 16, 2010

(PhysOrg.com) -- Elevated levels of a growth protein in the brains of Alzheimer's disease patients is linked to impaired neurogenesis, the process by which new neurons are generated, say researchers at the University of California, ...

Recommended for you

Global Ebola toll rises to 5,689: WHO

2 hours ago

The World Health Organization said Thursday that the global death toll from the Ebola virus had increased to 5,689 out of a total of 15,935 cases of infection, mainly in western Africa.

Ebola vaccine promising in first human trials

13 hours ago

Researchers say they're a step closer to developing an Ebola vaccine, with a Phase 1 trial showing promising results, but it will be months at the earliest before it can be used in the field.

At one month, US Ebola monitors finding no cases

16 hours ago

The U.S. program that requires weeks of monitoring for travelers from African countries with Ebola reaches the one-month mark Thursday. And so far, no cases of the disease have turned up.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.