The example was a six-layered column in the neocortex connected to a 14x14-pixel patch of the retina. There are, Olshausen said, about 100,000 neurons in that chunk of neocortex. That sounds like a lot of circuitry for a few pixels, and it is, but we actually have no idea how much circuitry it is. ...I found this quite simply amazing. The folks at the conference were interested in this because it means we're that much closer to understanding, and thus being able to artificially reproduce, the brain. However, this has other implications as well.
We are, however, starting to sort out the higher-level architecture of these cortical columns. And it's fascinating. At each layer, signals propagate up the stack, but there's also a return path for feedback. Focusing on the structure that's connected directly to the 14x14 retinal patch, Olshausen pointed out that the amount of data fed to that structure by the retina, and passed up the column to the next layer, is dwarfed by the amount of feedback coming down from that next layer. In other words, your primary visual processor is receiving the vast majority of its input from the brain, not from the world.
So the brain gets some input from the eye, but it's sending significantly more information towards the eye than it's receiving. This implies that the brain is doing a lot of processing and extrapolation based on the information it's been given. It seems that the information gathering part of the process, while important, is nowhere near as important as the analysis of that data. Sound familiar? Honestly, I haven't been keeping track of intelligence agencies of late, but the focus on data gathering without a corresponding focus on analysis certainly used to be a problem, and I think this finding is just another piece of evidence that says we need to focus on analysis.
This also applies to the business world. Lots of emphasis is placed on collecting sales data, especially on the internet, but unless you have a large dedicated staff to analyze that data, you won't end up with much in the way of actionable conclusions...