The brain is more like a CPU implemented in FPGA than a CPU synthesised into silicon.
Signals are only somewhat local - you get increased activity in this or that region and can correlate it with what happens in the brain - like power analysis attacks on crypto chips - the algorithm has to recover the data from the limited, noisy signal we are able to pickup.
You can't just put electrode in every single neuron to read its state like you can't put an electrode into every single piece of conductive metal on a chip - it would be to tight to fit and everything would stop working.
Signals are only somewhat local - you get increased activity in this or that region and can correlate it with what happens in the brain - like power analysis attacks on crypto chips - the algorithm has to recover the data from the limited, noisy signal we are able to pickup.
You can't just put electrode in every single neuron to read its state like you can't put an electrode into every single piece of conductive metal on a chip - it would be to tight to fit and everything would stop working.