Many people are aware that biological structure of our brain affects to our way of thinking. Not so many people are aware that the process is also possible the other way around: our thoughts also modify the biological structure of the brain. Our life experiencces from cradle to grave leave marks to its structure, our thoughts, ideas and views have an effect to our brain. Scientists were surprised to find out about placebo effect - how it did not not affect to result whether patients got real medicine pills or just pills without any medicine in them. Another well known example is when at old age partner dies and person loses his/her will to live - body and mind are tied together.
There's also theory about some people having born with such brain structure, which makes it very easy for them not to get involved with things that most of the mankind does (dualism, beliefs, seeking authority, grouping and so on). That makes them stand out already at very early age and term "enlightened" is sometimes put upon them. Still, even if that theory was true (personally I agree with it to certain extent) it does not make much difference - we all can change the structure of our brain. Not only unconsciously as we all do that all the time but consciously, seeing the cause and effect.
Here are some links about the subject:
http://en.wikipedia.org/wiki/Neuroplasticity
http://home.att.net/~meditation/soul.html
http://psyphz.psych.wisc.edu/web/News/wsj_1-19-07_begley.html