and EEG is noisy as shit (SNR wise) and fMRI has a 2-second lag and MEG's ill-posed spatially and repeatability is hard and imaging only gets you a few hundred

and EEG is noisy as shit (SNR wise) and fMRI has a 2-second lag and MEG's ill-posed spatially and repeatability is hard and imaging only gets you a few hundred microns into the grey matter and you can't do it in humans and "single units" usually aren't and you can't do that in humans either anyway and and and ... yeah, it's not easy.