Should be clear - if my understanding of this is correct, this is the computer reading letters directly from the VISUAL CORTEX. So, this isn't the computer reading a mind, so much as, a computer tapping the visual processing conduit. You probably couldn't "think of a letter" and have the machine figure it out. Something similar but more crude had been achieved in cats (horizontal lines vs vertical lines, using direct electrode implantation), about a decade ago.
What is impressive (if this article is not fraudulent or overinterpreting) is that it's a) done in humans, which realistically shouldn't be too much of a stretch from cats, and b) done non-invasively using MRI. We're NOT entirely sure what we're measuring with fMRI - it's supposedly increased bloodflow to the brain, but what that has to do with voltammetric activity is not 100% sussed out.
Aside: When I was in grad school there was this brilliant girl who somehow got sidetracked and burnt out in the lab she was in, started dropping out for weeks to isolate psychogenic compounds from desert cacti. For her qualifying independent proposal her presentation was basically two powerpoint slides that said "test out LSD in cats". Naturally, she failed, but she had this amazing hypothesis about how LSD works, and I understand why she wanted to do in cats.... And I'm 99% sure she failed to communicate this to her committee. She did, however, get a nice severance package and got to attend Albert Hoffman's 100th birthday party.
the vertical/horizontal line thing (http://web.mit.edu/bcs/schillerlab/research/A-Vision/A5-2.ht...) is cool b/c it demonstrates an actual neural correlate of consciousness and gives this concrete example of how information from the retina gets turned into higher-level abstractions as it moves into the cortex.
Visual cortex is not just processing what we are seeing trough our eyes, there is also feedback from higher brain regions back to the visual cortex. So when you are dreaming, your visual cortex activates.
Things get more messy though. For example when they take images from cat's visual cortex, they are much clearer because the cat is anesthetized and visual cortex only processes data from eyes. If cat would be awake, it would make reading the image very hard to read.
Sure, I guess I should have mentioned there's some feedback. That's why I said you "probably couldn't"... I don't think we know how much the activated visual cortex corresponds to the imagery we see when we are dreaming.
What is impressive (if this article is not fraudulent or overinterpreting) is that it's a) done in humans, which realistically shouldn't be too much of a stretch from cats, and b) done non-invasively using MRI. We're NOT entirely sure what we're measuring with fMRI - it's supposedly increased bloodflow to the brain, but what that has to do with voltammetric activity is not 100% sussed out.
Aside: When I was in grad school there was this brilliant girl who somehow got sidetracked and burnt out in the lab she was in, started dropping out for weeks to isolate psychogenic compounds from desert cacti. For her qualifying independent proposal her presentation was basically two powerpoint slides that said "test out LSD in cats". Naturally, she failed, but she had this amazing hypothesis about how LSD works, and I understand why she wanted to do in cats.... And I'm 99% sure she failed to communicate this to her committee. She did, however, get a nice severance package and got to attend Albert Hoffman's 100th birthday party.