An Interesting article in Psychology Today details how even one session of intense exposure therapy to target phobias can change our brain's responses to the feared stimuli. The study claims that even six months after the therapy, subjects actually "saw" the feared object differently. Perhaps, it is all just a matter of perception, after all.
http://www.psychologytoday.com/blog/the-other-side-normal/201206/your-brain-psychotherapy