`Dormant' inhibitory neurons: do they exist and what is their functional impact?

The concept of dormant interneurons is proving to be hard to define precisely. We argue here that the term is best used as an operational description of interneurons which are not lost from the epileptic brain, but which fail to perform adequately. We present evidence for the existence of functionally dormant interneurons in the tetanus toxin model of chronic epilepsy, and we explore the roles of a partial dormancy (and also of charge-screening) in the acute low magnesium model of epilepsy.