how do nerve fibers in the brain send messages

Answer 1

Emitting chemicals into the synapse to stimulate the next neuron(s).

I searched Google under the key words "neural messages" to get these possible sources:

http://www.google.com/search?client=safari&rls=en&q=neural+messages&ie=UTF-8&oe=UTF-8

In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.