Hypersynchronized and/or overly strong electrical activity in the neurons of the brain; seizure episodes are most often characterized by convulsions and altered mental states. Epilepsy is the medical term for sudden, frequent seizure episodes. Although seizures are often linked with epilepsy, they can have other physiological or psychological causes.
Example: An alcoholic man suddenly falls to the floor, unresponsive. After ten seconds of rigidity, violent muscular contractions begin.
Grinnell, R. (2016). Seizure. Psych Central. Retrieved on August 28, 2016, from http://psychcentral.com/encyclopedia/seizure/