I recently enjoyed reading this New York Times article,
How Walking in Nature Changes the Brain.
It provoked a further thought: if visualization is an important tool for an athlete's training (as studies show it is) could paintings serve as tools to visualize ourselves walking through nature, similar to the photos, videos, and daydreaming used by athletes, and therefore provide "brain training" opportunities in the places and times when physically getting outside is not possible?
I'll be thinking about this...