quickly. take a look at the brain here specifically, as that brain spins around you'll see there are two areas that are of critical importance, the frontal area in light purpel and the back area in dark purple is the hypocampus, these two areas need to be talking to each other to solve problems. the front area analyzes problems and synthesize it, and the back area is where you store memories and you can recall memories that can help you figure out the problem. when you're awake these two parts of the brain are talking to each other and there are also other areas of the brain that are talking to each other and it makes it harder and could interfere with that communication. when you are sleeping and more specifically when you're dreaming those two areas seem to communicate much more easily and that's why it's easier to solve a problem or synthesize something while you're doing this. you think your brain is asleep, it's really not, it can be working on something which is why people are told to sleep on