That's my concern as well, because I think it would go insane almost instantly. This would also render the whole project useless, you can't reasonably expect an insane brain to yield correct results. Or would it be a double trapped brain existing as chip, unable to move or communicate, witnessing it's neurons being used as a computing resource, but without being able to do anything about it.
It's very very scary, and there needs to be a process for testing for any type of consciousness and a plan for what to do if it's detected, I recommend just killing it instantly to prevent any suffering.
What exactly is doing the witnessing here, if the neurons are being used for computation? A lot of these comments seem to tacitly assume there is a little person inside our brains who is at the controls, and that organoid computing means that these controls are forcibly taken away, causing the magic little person to suffer horribly. It's strangely childish.
Why just human neurons for a human consciousness?
We know very little of what sparkle consciousness but the consensus seems to be that most living things experience it with varying degree. Even though most of us, conscious humans, are absolutely fine with millions of mammals being slaughtered without much care for their feelings.
There are so many unknowns with potentially horrifying answers.
We don't know what generates human consciousness. But we know the brain is a key part of it. At what point does a bunch of lab grown human neurons become conscious? Can it become conscious outside of a body? What would that experience be like if a lab grown brain used as a computer developed consciousness? And what would happen to that consciousness?
The potential energy savings aren't worth risking the potential horror.