Motion comes from the heart. Blood comes from the bone marrow.
It’s a factory that generates concepts to fight infections (bad thinking) and carries oxygen (brings life)
But the brain is not the source of the emotions but the entire nervous system. Likewise, the heart is not the source of blood but the bone marrow is which is placed throughout the body and picked up by the motion generated by the heart by the fluid currents it affords.
While I find it hard to fathom a “brain in a vat” scenario working in reality as I am partial to the “embodied cognition” and its family of related concepts – that our sensors and bodily interactions are a necessary part of systemic brain function along with environment…
..I also accept that the standard tradition of splitting functional systems apart for study purposes as valid enough.
I have yet to see an example of a human being functioning with only an autonomic nervous system but your answer was solid as the chemicals for emotion are ultimately generated within the brain itself.