In 1963 Heinz Kohut and Philip Seitz proposed an alteration in Sigmund Freud's diagrammatic structural model of the mind (1923). In their revised model (see Figure 1), they expanded the diagram to include the unrepressed unconscious activities and infantile impulses in interrupted contact with the preconscious layers of the surface. They called this the "area of progressive neutralization." It is formed through the process of transmuting internalization and consists of a drive restraining or neutralizing structure.
See also: Transmuting internalization.
Kohut, Heinz, and Seitz, Philip. (1963). Concepts and theories of psychoanalysis. In Joseph M. Wepman and Ralph W. Heine (Eds.), Concepts of personality (pp. 113-141). Chicago: Aldine Press.