Now I can't prove this but it's an interesting idea nonetheless. okay. Your brain is formed in a way to see the "physical" world, your used to seeing every day. When you alter the structure of it, through meditation, drugs, exercise or any mind altering activity, you change the structure of it to see into other dimensions. Even very small changes, that is a change even temporary it is molded different, so in a sense it sees a different world.
I read something similar around here a few years ago. It was someone asking what the world looked like outside of our brains, which i thought was a very interesting question. We all know that different animals all see water and trees differently but "what do they truly look like" seems like a nonsensical question to me, because they only 'look' like something if something is looking. I wouldn't say we see a different world though. We just see the same world in a different way - but that's probably what you meant.
There have been experiments which address this issue. In one kittens were raised in an environment made up of only horizontal or vertical lines. it was found that the cats could not track objects along unfamiliar lines, or often on the diagonal. Another involved special glasses which inverted vision. Common tasks were difficult to do for awhile but in time the subjects brain would flip the image upright so that everything appeared normal when wearing the glasses. Then there is the visual blind spot we all have. All showing that the brain "colors" what the eyes sense.
The brain is our bodies way to connect to the outside world. Along with the CNS, it is amazing how stimuli travels through our bodies. But on the philosophical side, I do feel that the brain perceives much more than we "see". Almost as if the brain only puts the world as comfortable for us as it can.
the title of this thread reminds me of a (science fiction) trillogy i once read called "g.o.d. incorporated", which i don't remember who wrote, and is probably long since out of print.