Rafael Yuste is Professor of Biological Sciences at Columbia University. He was born and educated in Madrid, where he obtained his MD at the Universidad Autónoma in the Fundación Jimenez Diaz Hospital. After a brief research period in Sydney Brenner's group at the LMB in Cambridge, UK, he performed Ph.D. studies with Larry Katz in Torsten Wiesel’s laboratory at Rockefeller University in New York. He then moved to Bell Labs, where he was a postdoctoral student of David Tank and Winfried Denk. In 1996 he joined the Department of Biological Sciences at Columbia University. In 2005 he became HHMI Investigator and co-director of the Kavli Institute for Brain Circuits at Columbia. Since 1997 he is visiting researcher in Javier DeFelipe’s laboratory at the Cajal Institute in Madrid. Yuste is interested in the structure and function of cortical circuits, the biophysical properties of dendritic spines and the pathophysiology of epilepsy. To study these questions, Yuste has pioneered the application of imaging techniques, such as calcium imaging of neuronal circuits, two-photon imaging and photostimulation using caged compounds and holographic spatial light modulation microscopy. These technical developments have resulted in several patents, two of which are commercially licensed. Yuste has obtained many awards for his work, including New York City Mayor's and the Society for Neuroscience's Young Investigator Awards. Finally, he is currently involved in launching the Brain Activity Map Project, a large-scale international project, sponsored by the Office of Science and Technology from the White House, that aims at measuring the activity from every neuron in a neural circuit.