Episodic memory - will tell you if you have seen the butterfly before. Episodic memory is the area most likely to worsen with age. Until recently psychologists have had to infer how memory works. Now technology let us see it - live. He will use all three main kinds of memory in this exercise.
Radioactive water is injected into the subject's bloodstream.
A subject is first show a series of pictures. Later, he will be shown the pictures again. When he remembers seeing one, blood will rush to the part of his brain he uses to remember and will activate the retrieval of the memory. Within an hour, Dr. Cheryl Grady can show areas of the subject's brain light up as they are activated- and the places in which different kinds of memories are laid down. What we really would like to do is to find out under what conditions will an older person activate these areas.