Occupational therapy approaches rehabilitation through the concept of "occupation", the component of human behavior regarding one's engagement in self-initiated, self-directed, adaptive, purposeful, culturally relevant, organized activity. Rehabilitation through occupation is a process, stemming from interactions among the three domains: (a) performance areas; (b) performance components; and (c) performance contexts. At the core of the occupational therapy is a sub-process created by patients and therapists through their actions and reactions to treatment. It is a significant sub-process because it sets into motion the use of occupation as therapy. It is believed that the appropriate, therapeutic use of occupation affects "performance" or how one functions.