A Journey between Neurons and Astrocytes: A Tribute to Giorgio Carmignoto.

The intimate relation between astrocytes and blood vessels was proposed by Camillo Golgi in 1870. Santiago Ramon y Cajal subsequently introduced the idea of astrocytes as regulators of functional hyperaemia accompanying neuronal activity in 1895. In 2003 Giorgio Carmignoto, Micaela Zonta, Tullio Pozzan and their colleagues revealed mechanisms of astrocytic control over vasodilatation. They demonstrated that astrocytic Ca signals are fundamental for translating neuronal activity into an increase of arterioles diameter, which in turn results in a local increase in the blood flow. This special issue celebrates the career of Giorgio, by gathering contributions of many friends of him, who will guide us along his scientific journey in this introductory paper, as well as presents original papers and reviews dedicated to astrocytes and their multiple functional role. It will become soon evident to the readers how, in every environment he has worked and lived, Giorgio developed strong relationships with people, always with the strong belief in the crucial role of collaborative effort in science, as well as in the value of friendship in life.