What Garrett Stanley and Yang Dan did in that work [1] is very cool, but it's a reconstruction. It is "what a cat sees" in the same sense that a false color image is "what a satellite sees". Essentially they regressed the activity of an ensemble of LGN neurons (visually responding neurons in the thalamus) with pixels on a camera to build a set of linear filters in space and in time. Then they used those filters to reconstruct the scenes based on the neural activity alone [2]. So it's what the cat sees in a kind of information-theoretic sense.
2. And actually on a reread this morning, it doesn't seem that they cross-validated their reconstructions. So perhaps their reconstructed movie frames are actually an overestimation. Regardless, there is no doubt that their technique works and it was a great starting point. Keep in mind: they did this in 1999!
If this is really what our cats are seeing, no wonder they seem to be scared or annoyed by us sometimes. Also, no point of buying colorful toys since they can't appreciate the colors.
Here's a link to the video: http://www.youtube.com/watch?v=piyY-UtyDZw