The concept of neuroglia as a connective tissue into which all elements of the central nervous system (CNS) are embedded was introduced by Rudolf Virchow (Virchow, 1856, Virchow, 1858, Kettenmann and Verkhratsky, 2008). Virchow never considered the cellular nature of glia; for him neuroglia was not more than a sort of extracellular binding element, and he often referred to it as a "Nervwenkitt" (i.e. nerve cement). Very soon, however, the cellular nature of glial cells was identified and many types of neuroglial cells were described. In the course of late 19th — early 20th century the cellular nature and morphofunctional heterogeneity of neuroglial cells were firmly established (Kцlliker, 1889, Andriezen, 1893, Lenhossek, 1893, Retzius, 1894-1916, Golgi, 1903). In the recent decades the functional relevance and versatility of neuroglia which is involved in all activities of the brain, from structural and metabolic support to information processing has started to be fully appreciated (Verkhratsky and Kettenmann, 1996, Kettenmann and Ransom, 2005, Volterra and Meldolesi, 2005, Verkhratsky, 2006b, Verkhratsky, 2006a, Verkhratsky and Toescu, 2006, Verkhratsky and Butt, 2007, Kettenmann and Verkhratsky, 2008, Verkhratsky, 2009). Furthermore, the evolutionary uniqueness of human glial cells (Oberheim et al., 2009, Verkhratsky, 2009) indicates their specific role in the formation of human intelligence.