Yes, this is fascinating. Of course, the threat assessment center must be calm to experience happiness or joy, so that part makes sense to me. Also, the memory centers are crucial, as well. If I see something that reminds me of a traumatic and painful event, my happiness will be replaced with pain and sorrow and perhaps fear or terror. On and on.

I have been studying moral decision making in the brain, because I am interested in the insanity defense. It is a similar overall setup in that virtually every single part of the brain is involved in making a moral decision in humans. It is not centralized, not in the least. It is extremely complicated, this process.