A null model for cortical representations with grandmothers galore

There has been extensive discussion in the literature about the extent to which cortical representations can be described as localist or distributed. Here we discuss a simple null model that encompasses a family of related architectures describing the transformation of signals throughout the parts of the visual system involved in object recognition. This family of models constitutes a rigorous first approximation to explain the neurophysiological properties of ventral visual cortex. This null model contains both distributed and local representations throughout the entire hierarchy of computations and the responses of individual units are meaningful and interpretable when encoding is adequately defined for each computational stage.