Two points:

• using stem cells so it remained biological brain cells, rather than a mechanical reproduction.
• they directly stimulate it with electricity and it then has a response to that stimuli, they don't seem to be hooking it up to check for additional processes; it's a step up, I guess, from direct stimulation for motor function in a frog - but not anything more revolutionary.

So, guess I'll need to update my post slightly, but the core point remains.

That said, I felt that they were saying for half of it that they were running Doom on a braincell using computer, rather than getting a braincell computer to respond to it for half the article. Oh well.