"Neurocientists know that a certain injury to your left temporal lobe can cause your left brain to become disoriented, and the brain might interpret activity within the right hemisphere as coming from another "self". This injury could create the impression that there is a ghostlike spirit in the room, because the brain is unaware that this presence is actually just another part of itself. Depending on his or her beliefs, the patient might interpret this "other self" as a demon, angel, extraterrestrial,or even god."

in "Physics of the Impossible" by Michio Kaku.

ass: Quinta Anilha