[Karlozkiller]

It's not well defined, but we can compare a dead brain to a brain in comatose to a fully awake and perceptive brain.

I assume, given what they say in the article, that the pig brain activity in the experiment was somewhere close to the activity of a dead brain or a brain in a coma.

They also explained that the blood-replacement they used contain a lot of inhibitive substances probably preventing the brains from being active even if they could.