Mark Schnitzer is a professor in Stanford’s departments of applied physics and biology. His work focuses on the innovation and usage of novel optical imaging technologies for understanding how large neural ensembles control animal behavior. In the past 10 years, his lab has developed several technologies now commercially available, including tiny microscopes small enough to be mounted on the head of a freely moving mouse. This technology was named one of The Scientist’s Top 10 Innovations of 2013 and Method of the Year 2019 from Nature Methods and is presently used by more than 500 neuroscience labs worldwide. His work on brain imaging was recognized with the 2010 young investigator award from the Biophysical Society. He was a member of the NIH BRAIN Initiative advisory committee that wrote the BRAIN 2025 report. His lab uses its inventions extensively to study the dynamics and coding properties of large neural ensembles. Their interests center on analyses of neural dynamics underlying various forms of cognition and memory across multiple brain areas and in brain disease. Recently, Schnitzer has been developing optical voltage imaging and several new types of fluorescence macroscopes for imaging neural activity across large areas of the neocortex. His trainees have been very successful, with 17 going on to become principal investigators.