How come our brain can become "smarter" after it has rested?

[Bill Angel]

This issue can arise when engaging in many different kinds of intellectual activity such as solving mathematical problems or doing puzzles.

I was woeking on a crossword puzzle and I got stuck. I was working on it for about 45 minutes and could not finish it because I could not think of words that matched the clues. So I stopped working on it, went outside, took a walk, ate lunch, and then returned to work on it. NOW after this break the words that I could not think of that matched the clues come to me and I finished the puzzle. I believe that the same phenomenon can occur when one is doing math problems. So what is going on here? What cured the "brain fatigue" that prevented me from discerning what the solutions were to the puzzle I was working on?

 

[iNow]

I'm over simplifying, but when you are actively concentrating, neural activity is focused on rather localized specific regions. When you rest, however, the brain then begins to try connecting that activity with other neural regions deeper in other areas... It tries associating it with past knowledge and experience.

 

In some sense, it's a process of anchoring. When the new distant connection is made and the "anchor" grabs hold, it often inspires new insights or realizations regarding the immediate problem you were previously working actively.

 

It's a bit like adding a different set of light to a painting. New features and textures and shadows become illuminated when those other bulbs switch on.

 

This article probably does a better job than I can of articulating it: http://www.psychologytoday.com/blog/conquering-cyber-overload/201005/sleep-success-creativity-and-the-neuroscience-slumber