http://www.iahf.com/nsa/20010214.html
Dont know if its true or not, but an interesting read.
For each direction+color an eye sees, there are some neurons that fire. I think the location of those neurons are known well enough to draw a BLURRY picture in neurons that a brain would see, but that accuracy from outside the brain, I doubt it.
Sounds like a mammoth waste of time all this monitoring.
Obviously the government would be interested in something like that, but I seriously doubt that if it's worth putting time into that it's been developed to any useful extent yet, again if it ever can or will be. I can think of several people right off the top of my head that I would've never heard of if such a program was developed to such an extent.