Davit,
Have you read the book by Rick Hanson called Hardwiring Happiness with references to neuroplasticity?
I'm not sure the environment makes my mood, since Nazi war camp survivors found ways of coping, so they developed better responses, in many cases.
My brain is mush these days, ironically, and I lost some interest as I'm about to pick up the book, since he apparently used mindfulness, which I found hard to connect with when I took a meditation course. I've always liked progressive relaxation.