Neuronal Cell Types in the Neocortex

One of the major challenges in neuroscience is to provide an answer to the question: Is it possible to define a set of neuronal cell types that is sufficient to describe the organizational principles of cortex and relate structure to function? In this chapter, we will provide an overview of some of the most common current cell type classification schemes and discuss the relationships between them and their present limits. Then, we will review some of our own work that aims to elucidate the relationships between soma location, dendrite morphology, axonal projections, and in vivo spiking of individual excitatory cortical neurons. Using these classification criteria, we introduce a set of 10 input–response–output excitatory cell types in the vibrissal part of rat primary somatosensory cortex, and discuss whether these cell types represent a “minimal set” that is sufficient to describe structural and functional organizational principles of whisker-evoked information processing