Illuminating Cellular Diversity in the Nervous System

A major goal of neuroscience is to understand how circuits of neurons and non-neuronal cells process sensory information, generate movement, and subserve complex processes such as memory, emotion and cognition. Elucidating the properties of neural circuits requires an understanding of the cell types that comprise these circuits and their roles in processing and integrating information. Since the description of diverse neuronal cell types over a century ago by Ramon y Cajal, however, we have barely scratched the surface of understanding the diversity of cell types in the brain and how each individual cell type contributes to nervous system function. Approaches for classifying neurons have until recently relied upon certain features including the differential expression of small numbers of genes, cell morphology, anatomical location, physiology, and connectivity - important descriptive properties that nonetheless are insufficient to fully describe or predict the vast number of different cell types that comprise the mammalian brain. To address this challenge, Professor Ngai and his colleagues are using single cell RNA sequencing technologies to characterize cortical neurons based on their transcriptome "fingerprints." Their long term goal is to develop a suite of technologies that can ultimately be scaled up to identify, classify and gain genetic access to the diversity of cell types throughout the entire mammalian nervous system.