This review article supports the following: (1) Hippocampal area CA1 serves as an associative match-mismatch comparator, (2) Voluntary movement strengthens episodic memories for goal-directed behavior, (3) Hippocampal theta power serves as a prediction error signal during hippocampal dependent tasks, (4) The self-referential component of episodic memory in humans is mediated by the corollary discharge (efference copy of the action plan developed by prefrontal cortex), and (5) Impairments in the production or transmission of this corollary discharge may contribute to some of the symptoms of schizophrenia.