Single Units and Grandmother Cells

This chapter turns to a more recent discovery in the human hippocampus, that of “concept” (or “grandmother”) cells. These grandmother cells are neurons that code for multiple aspects of the same person or object. The prediction that specific recognition cells were present in the brain had been made many years previously by vision scientists in Cambridge University and the Massachusetts Institute of Technology. Especially relevant for an understanding of conscious mechanisms was the observation that merely thinking about a person or image could increase the impulse firing rate of the corresponding concept cell, even when the person or image was no longer being seen. At about the same time Jerzy Konorski, in Warsaw, had argued for the existence of similar neurons (“gnostic units”) serving a number of functions.