What's the difference between a normal dream and a lucid dream?

I know that lucid is when you're aware that you're dreaming and non-lucid is when you're not aware. But what I'm wondering is, what's the difference in our brains that makes us have lucid dreams? Because I barely do anything different from before I had LDs. Except for doing a reality check when I wake up and then maybe again sometime during the day and I write down my lucid dreams. Nothing else.

What happened inside my head that made the switch to make lucid dreams happen?
Have they done any sort of tests to see the difference (inside our brains) between a normal dream and a lucid dream? I mean, why is it that I realise that I'm dreaming nowadays, but before I didn't? How did I learn to do that?

Hope this makes sense.

They've done scans that show that when you're dreaming the logical part of your brain is almost shut down. I guess once you realise you're dreaming and you can start thinking logically, it starts up again.

It's about awareness and when you realised that it is possible to be more aware in a dream, you started having them. Just knowing the fact is enough.

Look up John Allan Hobson if you are really interested.

Here is his wikipedia page Allan Hobson - Wikipedia, the free encyclopedia

He did a lot of neurobiological research.

Here is probably the most important part of his theories: The first step to lucid dreaming is recognizing one is dreaming. This recognition might occur in the dorsolateral prefrontal cortex, which is one of the few areas deactivated during REM sleep and where working memory occurs.