Also, there are big differences within the field of just something like analog signal processing, which will be very important for this project. The textbook linked (Sedra&Smith) is great if one plans to pursue analog in VLSI but not so great if one wants to do it on a PCB (I think Franco’s amplifier text is way better here).

Brain-computer is going to be very tough, even ignoring all the safety and physically wiring into a brain stuff. The signals are irregular, weak and fast which makes them very difficult (but not impossible obviously) to measure.