When I came to Duke, I started on those kinds of studies. Woolsey did the identification of auditory areas by evoked potential and he was the leader in the field and developed the field by recording from the brain using surface electrodes. Doing something sudden enough like tapping on the body, you would get the neurons to fire once and you could get a slow wave that you could record, and say ah yea I am touching on the right place, and this is an example of one of those early (Woolsey) maps in rabbit somatosensory cortex.
This is the traditional way he used to illustrate his data, which is to show dots on the brain where the recording electrodes were, and show the same pattern on little figurines the part of the body where you tapped, and you can see that you got legs up there, and face and oral cavity down here, that is a typical somatosensory map. That was done for auditory when you could not get a tone at a high enough frequency to really activate something. So it was done electrically by electrically stimulating the cochlea.
