a filling in of gaps in memory through the creation of false memories by an individual who is affected with a memory disorder (as Korsakoff syndrome) and is unaware that the fabricated memories are inaccurate and false

vs.

a sensory perception (such as a visual image or a sound) that occurs in the absence of an actual external stimulus and usually arises from neurological disturbance (such as that associated with delirium tremens, schizophrenia, Parkinson's disease, or narcolepsy) or in response to drugs (such as LSD or phencyclidine)