I've pretty much got the construct of the Animus ingrained in my mind and what she does with code is amazing. To be blunt about it and not go into all the tiny techno-deets, we'd be altering my machine to create a virtual reality simulator. Theoretically it'll be able to stimulate the brain close to if not in exactly the same ways as interaction in the physical world.
It has other uses, but I thought you might dig that one.