i have read reports on this research also, and share interest in the metaphysical and other concerns.
i suggest current thread title is misleading; the research in question is cultivating human brain tissue from stem cells in lab and implanting and continued cultivation as nodules on living mouses’ brains (the mice brains each are carried by individual mouses; making that explicit is why i am avoiding the usual grammatically preferable form of the plural mice). Recently scientists in that on going research reported specific aspects of vascular and other integration in the brain tissue, of the mouse and cultivated human tissue nodules.
As a Buddhist, to me some of the questions which occur are: was there a being in the human brain tissue? (I cautiously say, i don’t think so; it was detached from a source, triggered from stem cells, cultivated: it is analogous of a detached finger perhaps without suffering that might intail to previous finger owner.)
is there a being in the mouse whose body is being used? { imo, yes; sucks to be them, maybe. May all beings liberate.) By the way, they are alive, at least some of them, conscious, moving around, breathing eating pooping as volitionally as any mouse. They have also transparent domes over the brain(s).
could there be changes in mouses’ awareness and lives? (imo and reports support, could be in as much as brains are used by consciousnesses and or mind. Whether this affects beings’ kama is probably a thought path to insanity; kamma is a tricky object of thought unless an arahant who, i think, might not have interest except as it encourages liberation.) However, change is a constant, normal for any human or sentient, kamma effective only with human volition which is why any human birth is fortunate; am i off on any of that? Pls point it out.
Is there a being in the humans involved in this research? (imo, yes; sucks to be them, maybe. May all beings liberate.)
I suggest title be revised, and one consider carefully use of terms such as “intact” in the complicated situation, in reference to physical or metaphysical “objects” as we converse about this research.
i am thinking about some of your other questions, thank you for them.
edited quickly for some additional thoughts and typos. And, i might be inaccurate re: current tissue sources, you mention pig; human tissue might be just hypothetical or planned; is that correct?