It's hard to say exactly. When they capture Picard in Best of Both Worlds, a drone puts something to his neck and he freezes and goes "ahhhh" just before he beams out. It could be some sort of stun device, or it could be a nanoprobe injection.kostmayer wrote:When did the Borg assimilating people on the spot first happen in Trek? First Contact? In TNG it looked like they physically added implants to humanoid body - such that Picard was able to be restored by simply removing the implants again.
In First Contact we see them injecting nanoprobes, but they also do surgical stuff to implant larger parts. I've always assumed that this is standard practice, with surgery augmenting nanobots because it's faster or more efficient.