There is actually quite a ways to go before we have high fidelity macro models of the heart in action. (The numerical research I do is closely related). 3D fluid simulations are expensive. Hopefully the quasi-discreteness of the brain reduces the computational requirements for a high fidelity simulation.
Ha, that's funny, that model was the one UCL referenced in their kinda 'This is possible' motivation. I find it all very interesting, but gave up after a year as I felt like a lot of the models were going to be a bit flaky for the next decade and that was a bit of a culture shock (I was a physics student before).
