Comment by QuantumRoar

If I remember correctly, there are needle-like implants with around a thousand contacts and it is quite a difficult task to get the signals out of the brain. Either you have the ADCs directly at the contacts, which means you can't get your density of contacts up, or you have the ADCs outside which will give you a nightmare of wiring. In either case the technology to actually have an interface read out individual neurons is still quite far off, as far as I know.

I'm not quite sure about all of this, so maybe someone with up to date information on the technology can help me out here?