While some epilepsies have no known cause, there are instances when epilepsy can result from a brain injury. Trauma to the brain, such as suffering a stroke or an impact to the head, can cause seizures to develop. This may be due to inflammation (swelling) or infections, which can cause damage to brain cells and disrupt electrical activity in the brain. But what exactly happens that causes seizure activity to occur?
One way researchers can try to answer this question is by studying animal models of epilepsy. Within the brain, there are dozens and dozens of different chemicals that all play different roles. These include basic elements, like calcium, magnesium and potassium. These aren’t just minerals found in a multivitamin- they are all crucial for brain function. Brain cells, or neurons, use these elements to help communicate with each other. Our brains are surrounded by a liquid called cerebrospinal fluid, or CSF, that provides nutrients to the brain. The CSF maintains a particular balance of these elements so that the brain can function at an optimal level. Following a brain injury, this balance can be disrupted, which may cause neurons to misfire, possibly triggering seizure activity.
In order to study this, scientists use an artificial version of CSF in their experiments. Previous studies have suggested that CSF composition is altered following a brain injury. By carefully changing the levels of these elements within the CSF to mimic these changes, scientists can examine how communication between neurons is affected by their environment. EpLink researcher Dr. Liang Zhang and his team at Toronto Western Hospital used this model to study brain tissue from healthy mice. They surrounded the brain tissue with artificial CSF, but changed the composition so that the amount of magnesium was slightly lower than normal, and the amount of potassium was slightly higher than normal, mimicking the changes that may occur after an injury. They found that prolonged exposure (over 1 hour) to this modified CSF triggered seizure-like activity. These results suggest that using this modified CSF may shed light on how injuries such as a stroke or an impact to the head can cause seizures to develop.