What's on your Mind?
Remarkably, scientists can predict with near-perfect accuracy the last thing you saw just by analyzing your brain activity. The technique is called neural decoding. To do it, scientists must first scan your brain while you look at thousands of pictures. A computer then analyzes how your brain responds to each image, matching brain activity to various details like shape and color. Over time, the computer establishes a sort of master decoding key that it can later use to identify and reconstruct almost any object you see without the need to analyze the image beforehand.

http://www.popsci.com/node/42740/?cmpid=enews021110