[vinceguidry]

If one created a physical substrate that neurons could transmit to and from, then embedded it in the brain, you could create consciousness in that substrate. A primitive analogue of this has been done where they attach electrodes to the tongue and fired them in a pattern suggestive of a video feed, eventually the brain started to understand it as another 'sense'.

Should one start brain-interacting directly with a substrate, the substrate could be powered independently and persist after separation. If separation occurred after natural death of the host, you could say that it 'uploaded' it's consciousness to the substrate.

[quahaug]

That's just a replay attack. The consciousness is still bound to the cells. No new, unique information is generated without the presence of the cells.

The term "uploaded" is being subjected to special semantics in this case. Consciousness is not transferred over to the receiver by the act of transmitting a signal.

If I make a telephone call, and leave a voicemail message, the answering machine does not get up and walk around. Even a sufficiently advanced voicemail recorder would only be an interpretation of artifact left behind by a creature, and not the original being.

[vinceguidry]

But if the substrate had artificial neurons, that could do everything normal neurons could, then it's plausible that consciousness could copy everything over. At that point, the only thing binding consciousness is the 'idea' that it belongs to the cells.

If you separated them before the host dies, then you'd have copied the consciousness into the substrate, and they would exist separately until you reattached it.

Wait until the host dies, then the consciousness would experience that death yet still persist. It would carry on experiencing through whatever senses the substrate offers.

Notice that it's not just a signal being transferred, it's the actual mechanics of consciousness, neurons firing and communicating. When the substrate, connected to the brain, communicates, it's just as if you added brain cells. So it's not just a signal, it's actual thought.