By the same logic, you could ask "what part of a computer 'is' the computer? The CPU? The hard drive? The RAM? The TPM? The power supply? The sum of all peripherals? Etc"

You could ask all kinds of philosophical questions about this, but at the end of the day, there are parts that are easily replaceable and parts that are harder if you want to preserve the identity of a particular machine.

E.g. while RAM, CPU, GPU, power supply etc are all essential for running a PC, you can also swap them out without many problems. In contrast, the data on the hard drives or the TPM might be hard or impossible to restore.

In the same way, I'd still see the brain as the center of the self, because so much cognitive information is stored there.

A very powerful meditation practice is called self-inquiry. One version of it is after you calm your mind down (say with breath meditation) you look for where u think u r. Wherever that is, ask yourself if that’s where u r, what is looking at it? Keep going, don’t intellectualize it, and keep looking.

>but it is also possible to live in more harmonious relation between the head, heart, and gut — all the intelligence centers.

Aren't those the supposed locations of the "chakras"?

"[i]f you look closely at our nervous system, you’ll see that there are neuronal clusters distributed throughout the body. Human computation is better understood as distributed than centralized."

Interesting article, Douglas Hofstadter's book https://en.wikipedia.org/wiki/I_Am_a_Strange_Loop takes it a step further and says that parts of our consciousness/soul lives outside of ourselves and in the minds and brains of others. Since one can generally guess how person you know would respond in a given situation, such as how a spouse might be able to know exactly what their spouse would say/do, and in that sense our "souls" are distributed. It's a bit more nuanced than that, but I think that gets the point across of how parts of ourselves live in others.