These cases and others — from the commonly known (Alzheimer's disease) to the highly unusual (
Ecstatic epilepsy, in
which seizures convey a feeling of transcendent
joy) to the almost supernatural (the Doppelganger effect, where people see and interact with a duplicate of their own body)-- are linked, Ananthaswamy suggests, by the simple fact that each condition involves disruptions in an area of the brain where the «self» is thought to reside.