The brain, and the heart are both used as chakra storage's if I may. Chakra is the main solvent to everything within the Narutoverse; Chakra supplies life, and death, chakra controls people, chakra basically is the universal solution to everything. So why exactly wouldn't a chakra transmitter such as the heart be ale to perform basic instructions similar to what the brain can do (this is Naruto after all).Dr Proof I made a reply on that already on your thread. Here I will Quote it:
Also Jiongu may play a huge part in this, as it may seem that the threads/tendrils have a symbiotic type relationship with Kakuzu. Who knows Jiongu itself could be similar to Samehada, and could actually be what supports Kakuzu's many functions.
We cannot concur if Kakuzu has a brain or not, but this is a theory (one of the best on base if I may say). So we cannot really be assured if it's correct or not, but at the very least it's plausible.