Top 8 Quotes by Oliver Sacks

I think hallucinations need to be discussed. There are all sorts of hallucinations, and then many sorts which are okay, like the ones I think which most of us have in bed at night before we fall asleep, when we can see all sorts of patterns or faces and scenes.

With any hallucinations, if you can do functional brain imagery while they're going on, you will find that the parts of the brain usually involved in seeing or hearing - in perception - have become super active by themselves. And this is an autonomous activity; this does not happen with imagination.