Anne C. ponders long-term maintenance of the brain: "One of the most fascinating things about the brain is how it must simultaneously change constantly over time (in response to new information and other inputs) and maintain the aspects of its structure that permit it to keep functioning as a person wants it to as he or she ages. This is true for the body as a whole, of course, but particularly interesting to consider in the case of the brain, as (unlike other organs and parts, which can be transplanted or replaced by prostheses) the brain is unique to each individual in such a way that you wouldn't ever be able to replace it with another and expect to get 'the same person' as a result. ... It is this uniqueness and irreplaceability of brains that makes them of special concern in thinking about healthcare across the lifespan. ... I [think] it more than reasonable to surmise that the conditions presently grouped together as 'the dementias' will likely someday: (a) subsume the phenomenon of milder memory loss and progressive cognitive difficulty currently considered 'normal aging', and (b) become amenable to preventative, maintenance, and rejuvenation treatments."