As for your "brain is just a receiver for outside thoughts" idea, it's one I've heard many times before, and while quite a clever idea, it's clearly false when we take into account the research we have done into the brain.
For the most part, different parts of the brain can be mapped to very specific functions, and interacting with them in certain ways can cause very consistent results. This is consistent with the brain being the cause of thoughts, rather than a receiver of them.
For example, we can actually CAUSE the brain to have certain thoughts. If you compare that to your receiver analogy, a receiver can distort thoughts if we damage it, but it cannot consistently create certain thoughts by manipulation alone.
If we think of your example as a TV, with the brain being the antenna for outside television broadcasts. What you are suggesting, is by tweaking the antenna, we can cause a completely different program to be displayed on the TV out of thin air. This is obviously impossible, the TV would have to have the ability to create that program by itself, without any outside help, and that is what the brain is able to do. That's why it cannot just be a receiver.
"All of our behavior can be traced to biological events about which we have no conscious knowledge: this has always suggested that free will is an illusion."
- Sam Harris