The organizing principle for all of these efforts must hearken back to the founding of modern neuroscience by AZD6244 supplier Ramon y Cajal (1899), who first saw and understood the fundamental importance of identification, characterization, and comparative analysis of the great diversity of cell types present in complex nervous systems. We thank Dr.

Charles Gerfen for the image appearing in Figure 1. We wish also to thank Melissa McKenzie, Danielle Van Versendaal, and Edmund Au for their help in creating Figure 2. N.H. was supported by a Howard Hughes Medical Institute (HHMI) Investigator Award, an NIH NINDS HSSN271200723701C GENSAT contract, a Simons Foundation SFARI 2009 Research Award, an NIH/NIDA ARRA Grand Opportunity Award, NIH/NIMH 5 P50 MH090963 P2 Conte Center Project 2, and NIH/NIDA P30 DA035756-01 Core Center of Excellence. G.F. was supported by NIH grants (RO1MH071679, RO1MH095147, R01NS081297, and P0NS074972), the Simons Foundation, and the State of New York through the NYSTEM initiative. “
“The term “glia” (from the ancient Greek for glue), coined by Rudolf Virchow in 1856, seems to carry both literal and figurative

connotations. Virchow thought glia to be support cells, a putty holding things together. However, it is perhaps pertinent that in Virchow’s time glue was a rather ignoble substance made from the hooves of knackered horses. Whether intentional or not, his descriptor implied a passive and uninteresting selleck function for glia, placing them low in the neural hierarchy. However, attitudes are shifting with new studies that show that glial and cells are essential modulators of brain function and health. In 2008, a previous Perspective on this topic in Neuron ( Barres, 2008) highlighted many then newly identified and unexpected functions of glia and predicted many more. A mere 5 years later, the list of developmental mechanisms of and roles for macroglia—i.e., oligodendrocytes, astrocytes, and their precursors—has expanded significantly. Progress in the field has been comprehensively covered in many outstanding recent reviews ( Aguzzi

et al., 2013, Attwell et al., 2010, Emery, 2010, Eroglu and Barres, 2010, Freeman, 2010, Molofsky et al., 2012 and Nave, 2010). This Perspective is not meant to be a comprehensive review of glial cell biology. Rather, we hope to highlight emerging ideas in the field, discuss how approaches are rapidly evolving, and suggest priorities for the future. We will focus primarily on macroglia (with apologies to microglia and Schwann cells) and adopt the speculative viewpoint that the long evolutionary time frame for codevelopment of neurons and glial cells, from simple organisms to higher organisms, indicates the fundamental importance of glia in invertebrates and predicts their increased diversity in vertebrates. We envisage that tools of developmental biology and cross-species analysis will yield exciting new insights into the precise functions of glial subtypes from the simplest invertebrates to man.