What if some hypothetical substance, or even a high dose of a common substance, could essentially force a person into a state of "terminal lucidity?"

Sometimes, dementia patients will suddenly seem like their old selves to their families again immediately after dying. A video interviewing a doctor somewhat euphemistically stated that this was caused by the brain defaulting to other areas to control behavior, as opposed to any kind of recovery of the usual networks. Almost like a kind of autonomous network that could help you be you normally, but now is the whole you. Then, the doc said that it's nice that it helps the families say goodbye to their loved ones. I'm bad with hints, but this almost seems like an admission that their relatives aren't even there in this state; it's just another part of their brain shaped by this behavior.

That said, what if it were possible to do this to an adult, through all but muting the usual limbic and cortical sources of consciousness, except these autonomous parts that perhaps I find myself using when I order food or give my date of birth to the pharmacist.

Or perhaps, just the part of the brain that reflexively says "I love you" to your relatives, perhaps since this is just what you were raised to do, not a literal expression of appreciation.

Imagine if you could put a patient into this philosophical sleeper agent state, where they can still perhaps form some memories in the alternative mechanism, still react to pain, and still talk, walk, drive, work a register, take patients' vitals, or even handle a legal case, since everything was overlearned.

This patient might not listen to their favorite music by true choice, nor would they get chills or entrain to it, but if you asked them for their favorite song, they'd tell you.

This patient might not feel a true emotional connection to you, but knows how to fake it.

This patient might be operating purely on what would have been called reflex behavior, with key limbic pathways dampened and/or placed into a "spammed" state, and the internal default mode network also impaired, while areas more focused on cooperating with others are more or less intact.

These patients also still look conscious, awake, and alert to others, and with their overlearned behavior, may be safe to drive, but they might not actually have any personal pursuit of where to drive to.

And it may perhaps be possible to put someone in between, where they rely on this overlearned network more than they otherwise would have, or find their more conscious selves having less control or even care to override their autopilot.

Perhaps they'll default to how they're raised. Atheists become the Catholics they grow up, promiscuous people default to the prudence (or prudery) of their families, etc. Introverts by choice may seem nicer and more sociable, but the bond they get with you is reflexive and perhaps formerly reinforced in early childhood. It might bear zero resemblance to the bond they had with the former few people they got along with.

And ironically, they may lose all emotional context in the true system over their past memories, while still being able to tell you details of their childhood. They can tell you they used to game or skateboard a lot, but may be emotionally distant from the act. They can just tell you they did it.

An extreme possible example may be the studies done on people taking propofol who could be interviewed in their sedation but then immediately forget it. What's doing the talking, or remembering what was said?

And I honestly wonder what the true mechanism of action of antipsychotics and high dose antidepressants is.