Neuroplasticity - while not a concept unique to OT - holds tremendous application for neurorehabilitation provided by OTs. Neuroplasticity refers to the brain's ability to adapt and change over the course of one's life - not just in the period of development. This is particularly important when considering rehabilitation following a neurological event such as a stroke.
When I was in OT school in the early 1990s, the accepted thought was that a person with a stroke would see maximum recovery within 6 months following the stroke. Consequently, if a person was seeking therapy several years post-stroke, it was thought that the person had limited rehabilitation potential and it was often difficult to receive approval to provide services. With the improved understanding of neuroplasticity that has occurred in more recent years, it is now accepted that the brain has the ability to modify itself even years after a stroke. More specifically, following a neurological event such as a stroke, it has been demonstrated that the brain has the ability to "rewire" itself.
This understanding has provided the explanation as to why interventions such as constraint induced movement therapy provides such notable results. In this approach, "forcing" the use of the affected upper extremity appears to unmask neural pathways that reorganized or sprouted following the stroke. However, the person learned not to use the affected upper extremity based on their unsuccessful attempts initially following the stroke.