"Hanson said the brain is "Velcro" for negative experience and 
"Teflon" for positive experience.
Human evolution favored the wary, the vigilant, the anxious. Animals, 
accidents, and enemies
were out to get us. A part of the brain called the amydgala 
contributes to this "negativity bias" of
the brain. It is primed to label stimuli as threatening. "Negative 
experiences trump positive ones
and lead to vicious cycles," said Hanson. "Unless this bias is offset 
by many positive
experiences, the result is an unfairly negative view of oneself and 
the world, and a slowly
accumulating tilt toward the negative in emotional memory.'7 The 
brain's negativity bias plays
out in our personal lives, and it plays out in the bloody events that 
make news from day to day."

http://tinyurl.com/84l4l6

and more papers on meditative practices and neuroscience:

<http://neurospirituality.blogspot.com/>http://neurospirituality.blogspot.com/

http://www.wisebrain.org/


"People Who experience mood swings, fear, voices and visions"