I stumbled on this work while researching cyborgs. There's quite a bit of jargon on this official page. The main idea (as I understand it) is that previously, when you got an amputation above the elbow (for example) the bicep and tricep muscles became dead ends. They would just attach the ends of the muscles wherever feasible. Apparently the act of one muscle like the bicep contracting (agonist) while another related one like the tricep extends (antagonist) is a really important feedback loop in our brains. AAMI essentially restores this feedback loop, making the prosthetic feel like part of the body. The lead researcher is apparently himself a double amputee.

Osseointegration was another example of interesting real-life cyborg technology that I stumbled upon.