Burst suppression describes an EEG pattern where periods of high-voltage brain activity are interspersed with periods of no brain activity. It is associated with unconsciousness caused by coma, anesthesia or hypothermia. The difference between higher and lower states actually increases with the level of unconsciousness. As such, it is a very good indicator of the seriousness of a coma and can assist a physician with a prognosis.
The underlying cause of burst suppression is the action and supply of neurotransmitters which alternately fire off uncontrollably, then become depleted.
Although the pattern was originally believed to apply to the entire brain at once, further study shows that different areas of the brain can and do exhibit burst suppression at different times.