Subject: Long term memory

When I ask others of my age{75} to try to remember something specific 
such as the arraingment of their kitchen when they were 10 years of 
age.Something that they have had no reason to think of for many years 
they are immediately able to recall subject in detail.
My question then is; how is such visual [or any other ]in formation 
stored and how is it recovered. I am hoping the answer will be very 
specific.What chemical compounds etc.