One Decade Later: What has Gene Expression Profiling Told us About Neuronal Cell Types, Brain Function and Disease?

The many diverse functions executed by the central nervous system (CNS) are mirrored in the diverse shapes, connections, and firing patterns of its individual neuronal cell types. Furthermore, distinct neurological diseases are the result of defects in specific neuronal cell types. However, despite the significance of this cellular diversity underlying brain function and disease, we know relatively little about the genes that contribute to purposeful differences among regions and cell types within the brain. A major challenge in this endeavor is the paucity of markers that define the many regions and cell types thought to exist. Cataloging the neuronal cell types and cell- and region-specific marker genes requires novel avenues that enable researchers to define gene expression profiles of brain regions and individual neurons and to apply this information to understand functional and structural properties in the normal and diseased brain. Functional genomic approaches such as gene expression profiling offers the exclusive opportunity to glimpse the detailed inner workings of distinct neuronal cell types. Recent studies have applied microarray technology in unique and novel ways to understand the molecular mechanisms that underlie such neuronal diversity and their potential role in brain diseases.