Glia: much more than the neuron's side-kick

Neuroscientists should have known better. Ramon y Cajal, a visionary whose contributions on neuronal morphology and circuitry have dominated modern neuroscience, also made significant observations about glia, the non-neuronal cells in the brain. Yet his pioneering work on glial cells was all but ignored. Over a century ago, he recognized the great numbers of glia in the brain and their intimate association with neurons. Though their function was at that time a mystery, he predicted that glia must be doing more than simply filling the spaces between neurons. Not surprisingly, Cajal was correct. Neuroscientists are now catching up and discovering that glia not only support a number of essential neuronal functions, but also actively communicate with neurons and with one another. By doing so, glia influence nervous system functions that have long been thought to be strictly under neuronal control.