A seizure happens in the brain. It is the result of unusual electrical activity that can make someone act or think different for a short period of time. Seizures can be the result of brain injury, genetics, brain tumors or malformations, infections, stroke, or heredity. But in about half the cases of epilepsy and seizures, the cause is unknown. If you have epilepsy, knowing what may trigger your seizure is very important, so you can do your best to avoid them. For example, make sure you get enough sleep. Avoid undue stress. Know your body as best you can.