I don’t say AI is sentient but what do you expect out brain to do in the end, it’s likely just some matrix operations and integration and other stuff arranged in a very intricate way.
The whole human architecture, including everything else, can easily be expressed as just over 2 GB (2 bits per base pair), and compressed to under 300 mb (half of the gains are just specifying the length of some sections rather than everything). And that includes everything from the cpu architecture to toenail building, not just the brain.