There are some non-invasive things like fMRI, fNIRS, and EEG that can measure ac...

cafebeen on July 9, 2015 | parent | context | favorite | on: Understanding Neural Networks Through Deep Visuali...

There are some non-invasive things like fMRI, fNIRS, and EEG that can measure activity to some extent, but those are all at far coarser resolution than single units.