Thanks. If I got my hands on it I'd read it in its entirety.
I tried looking at Brain and Behavior Research Foundation. They talk about current studies they're doing and from that I can piece some things together, but yes it is a LOT.
Wow, this is a very big question. I have entire books explaining this. If you are interested in this I suggest you search neuroscience of anxiety disorders. Or brain science and anxiety disorders. Let us know what interesting information you find.
For lots of detail on this question you might want to find the book, The Anxious Brain by Margaret Weherbuerg and Steven Prinz. It is for professionals who work in mental health though so you might want to just skim it.