Yes, as ay says the "format" of neurons isn't actually that mysterious. It's actually one of the few things we do know. We also have a pretty decent comprehension of the encoding for audio and visual stimuli, at least as they come out of the sensory organs. It's not a perfect understanding, but it's not a complete mystery either. (Cochlear implants actually to some extent directly interface with the nervous system.)
(Actually we can trace the visual input some ways up the core processing path, too, which is interesting. I don't know what the state of the art is now but a few years ago when I was learning about this in school we had a clue that there's a lot of neurons dedicated to edge detection, orientation detection, and movement detection. It's not a miracle that humans see better than computers, rather a lot of our brains are dedicated to doing a lot of computation in parallel long before this rises to the conscious level.)
Picking an appropriate encoding for a new sense may not be absolutely trivial but it is something we might be able to do today. What I wouldn't expect to happen any time soon is the direct memory interface, or anything that interfaces any more directly than a simulated sense or simulated limb. I can imagine a phantom limb interacting with a simulated computer desktop and overlaying the visual system without more than the expected leaps in technology; imagining something that allows you to simply remember Wikipedia just as if you memorized it is much harder to even imagine.
(Actually we can trace the visual input some ways up the core processing path, too, which is interesting. I don't know what the state of the art is now but a few years ago when I was learning about this in school we had a clue that there's a lot of neurons dedicated to edge detection, orientation detection, and movement detection. It's not a miracle that humans see better than computers, rather a lot of our brains are dedicated to doing a lot of computation in parallel long before this rises to the conscious level.)
Picking an appropriate encoding for a new sense may not be absolutely trivial but it is something we might be able to do today. What I wouldn't expect to happen any time soon is the direct memory interface, or anything that interfaces any more directly than a simulated sense or simulated limb. I can imagine a phantom limb interacting with a simulated computer desktop and overlaying the visual system without more than the expected leaps in technology; imagining something that allows you to simply remember Wikipedia just as if you memorized it is much harder to even imagine.