We usually have a pretty good idea on what we are thinking, just because we are thinking! However, what we perceive is just a fraction of the whole story that is going on in the hundred billion neurones in our brain. Most of what goes on is actually disregarded like all the sensations coming in from our joints, the related computation and the feedback to the muscle to keep ourselves standing (or sitting or walking).
Now a neuroscientist, Adam Gazzaley, at the UC San Francisco has come up with a way to process electrical signals produced by firing neurones and detected by electrodes mounted on a cap placed on the head and visualise them on a screen as rays of light flowing from one part of the brain to another.
Adam has created a technology, he calls it appropriately "GlassBrain", that is quite impressive in its ability to render the flow of activity within the 3 pound universe. I am not sure on the "fidelity" of this tracking, actually I doubt about it, but I still recognise that it is really impressive to look at what is "broadly speaking" going on in our brain.
There have been more precise tracking on neurones firing using markers in a zebra fish, but seeing what "might" be going on in our own brain as we think, move, look gives a completely different feeling.
I should also say that I am pretty sure that we will reach a point (and not too far away in time) when we will really be able to see with great accuracy at what is going on in our brain in real time.