Steve Johnson, in his book Where Good Ideas Come From, which I've written about before, defines an idea as this:
"A good idea is a network. A specific constellation of neurons--thousands of them--fire in sync with each other for the first time in your brain, and an idea pops into your consciousness."
I oscillate between being overwhelmed by ideas and not being able to enact them and being bereft of any idea that is not stale and dull. When I think about it in terms of neurons, this all makes perfect sense.