So a quick google says it uses 70 millivolts.

Which means the human brain has a metric fuckton of amperage (probably explains the heat)

285 Amps.

To safely carry that current you need 95mm2 of copper wire.

9.5cm X 9.5cm

So cubed, because 2d doesn't make sense is approximately 1000cm3

The human brain is 1300cm3

That means the human brain is just one fat copper wire

It's a shame we can't up the voltage a little bit and save on brain size