In a partial seizure, the hyperactivity is unilateral in the brain and focused in a localized area. Behavior is often described as convulsive, but can still vary from mild to severe. These are the seizures commonly referred to as epileptic. Mild epileptic seizures are described as Petit Mal while the more severe ones are termed Grand Mal. The most commonly encountered secondary seizures are those resulting from electrolyte imbalances, drug withdrawal, or lesions of brain tissue from trauma or cerebral blood supply disruption as with strokes.
Arousal is a level of consciousness involving the cerebral cortex.
In fact, arousal levels can vary normally from sleep to high anxiety levels in the course of a normal day s activity. These arousal levels are controlled by brain structures deep within the cerebral hemispheres and brain stem which send action potentials to the cerebral cortex where consciousness is centered. Such activity arouses one from sleep and controls the consciousness levels characteristic of daily activity. Injury to any part of the RAS can result in coma, the severity of which is determined by brain area involved. Some coma states resemble sleep without the characteristic REM eye movements characteristic of sleep cycling.