Visualization - inside our mind

This note is on that portion of our brain (supposedly, I do not know which portion) which is responsible for our mental visualization of something.
I find myself a very visual person. Most often, in a conversation or left to myself in a thought, I would have a trainload of pictures running through my mind. I am not sure if this is very normal; given a chance I would guess negative and hold it as one reason for overall abnormality people attribute to me :)
I wonder why and how this happens. How part is more astonishing to me, as I enjoy it why is not that important. Especially as the subject becomes more abstract, the association of the words to pictures in your mind takes a more curious bend. It is one thing to have a flash journey through the arteries and veins and blood vessels when you are curiously talking about strangeness of human physiology and its enormous complexity and incomprehensibility, say during a casual conversation over practically everything during a lunch. It is quite the opposite, when immersed within yourself over a bus window, you are vaguely aware of a collage of thousand of things and events taking place in the universe surrounding you, and you suddenly, have flash memory of a few second shot of a movie you saw thousand years back and never remembered explicitly ever since. I never ever get the logic that what correlation of things and state at that moment led me back to that particular scene.
I am sure this happens to all of us, more often for some people less for some. It is strange how we see things. But I think it is stranger how those things gets stored somewhere, and quite unexpectedly, years later get revived through millions of recognized and unrecognized stimulus. We probably would not have otherwise remembered the same thing in our entire life.
That is all. Let me end with the movie scene I recalled above. But having wasted a few minutes of your time which I am thankful for, I must warn you that it is not like the greatest movie scene ever made. I just realized that for no apparent reason, it will stay in my mind possibly for ever.
Rahul Bose in the role of a corporate bigshot who earns a fortune for every hour he gives to his client, but unhappy since he lost his wife in an accident he holds himself responsible for. Kareena Kapoor portrayed a prostitute who earns a meager living. Both meet stuck in heavy rainy night. Initially the lady tried to seduce the only prospect in sight, but soon stopped. As they spend the night through a series of unexpected hazards, a deep friendship forms. Few days later, as Rahul comes back to find her in those dark streets, he spots her from a distance, lighting a cigarette, and a trainload of pictures suddenly rushes through his mind. A wonderfully collaged 10-12 shots each staying a fraction of second. A few incidents spread through his life played back momentarily, ending with a shot of his wife once saying to him - " .. baas, pyar hona chahiye ..."