What is a grandmother cell? and how would you know if you found one?

Abstract

The key claim associated with a grandmother cell theory is that single neurons selectively represent one complex 'thing' (e.g. object and face). However, this theory is often mischaracterised in the cognitive and neuroscience literatures. I summarise two common confusions here. First, critics of grandmother cells often fail to distinguish between the selectivity and sparseness of neural firing and, as a result, predict (incorrectly) that one and only one neuron should fire in response to a given input. Second, critics often fail to distinguish between what a neuron responds to and what it represents - as detailed below - and as a result, predict (incorrectly) that a grandmother cell should fire in response to one and only one thing. I argue that these two confusions often lead to the premature rejection of grandmother cell theories. © 2011 Taylor & Francis.