President Obama announced earlier this week that he wanted to spend 100 million dollars to begin mapping the human brain. This money would just get the project started - it would take millions more dollars and most likely decades to complete the project. That is because there are approximately 100 billion nerve cells in the brain - that is as many stars as there are in the Milky Way Galaxy. In addition to all of the cells there are all of the connections between them - over 1 trillion connections. One brain cell can have as many as 10,00o connections.
Our brains are amazing and probably hold a lot of information that would be helpful to know, but part of the problem is that scientists don't know exactly what they are looking for yet. That is what happens when we explore new things.