While you’re snuggled up in bed at night, your brain doesn’t just switch off. In fact, it’s hard at work doing all sorts of incredible things. From organising your memories to solving problems you didn’t even realise you had—your brain stays busy even when you’re dreaming. Sleep might look peaceful from the outside, but on the inside, your brain is buzzing with activity.

So, what really happens in your brain while you sleep? Why do dreams feel so real sometimes? And how does your brain know when it’s time to wake up? In this article, we’re going deep into the science of night-time thinking. I’ll walk you through what scientists know (and what they’re still figuring out), and by the end, you might never think of bedtime the same way again.