- A grid of electrodes on the tongue, activating with a pattern fed from a camera. After a while, blind experimental subjects reported actually seeing what the grid displayed.
- A belt of buzzers hooked to a compass. The buzzer closest to magnetic north was always active. After a couple months, subjects weren't really conscious of the buzzing, but got a really good mental map of their environment and their position in it. They could navigate unfamiliar environments much better than before...and then much worse, when the experiment ended.
There are also some well-known cases of blind people using echolocation pretty effectively, without any special hardware.
Don't have links handy, unfortunately.
How does that work? A single neuron is a single neuron. My understanding is that the brain has lots of neurons and also they are assembled in certain "NN architectures" that are far more advanced than what we currently have. But I think that if you go the the single neuron level then they are pretty similar in terms of problem solving capabilities.
That's what I remember and I just took some neuroscience courses. There are multiple books out there attempting only to describe behaviour mathematically, let alone describing the underlying mechanisms, which is true "here be dragons" territory.