Definition: Mind, as divided into conscious, preconscious, and unconscious in Sigmund Freud's topographic model.
By Nancy Schimelpfening, About.com Guide
Updated May 07, 2008
About.com Health's Disease and Condition content is reviewed by the Medical Review Board
Bring your life into balance with tips on good nutrition, family fun, and healthy activities. More >
Learn how heart disease might be interfering with your love life. More >
©2010 About.com, a part of The New York Times Company.
All rights reserved.