This strikes me as going too far.
the justification (upfront which is not as usual for most papers I come across which explain what they did that was so cool first) is something like it's hard to determine if what drugs we give to a brain is just brain based or is the darn body getting involved too.
But you know, if I understand that right, then we are mostly going to want to care about the brain and body together - cos that's how most of us function.
I get it's an engineering challenge. I also get that experimenting with certain things is just off-limits, foetuses being the first thing that come to mind.
I am a huge proponent for increasing science funding every day of the week, for undirected research because we don't know what we don't know, but sometimes we just need to say, find another way.