What’s the science behind the “aha” moments that have inspired great thinkers and Oprah alike? A team of Israeli researchers set out to discover what happens in the brain when we gain sudden insight.

In this study, subjects viewed camouflaged images that were impossible to decipher. Researchers then revealed the true image, creating an “aha” moment (a shift in perception from unknown to known). A week later, subjects viewed the camouflaged images again and tried to recall the true image. When subjects showed activity in the part of the brain that processes emotions (the amygdala), they were more likely to remember.

Strangely, the pics themselves didn’t elicit emotion, yet the amygdala still lit up, suggesting that our emotional brain helps us commit insights to long-term memory.