Department of Neurobiology, Stanford University, Stanford, United States
Michael M Pan
Department of Bioengineering, Stanford University, Stanford, United States; Department of Pediatrics, Stanford University, Stanford, United States
Stephen W Evans
Department of Neurobiology, Stanford University, Stanford, United States; Department of Bioengineering, Stanford University, Stanford, United States; Department of Pediatrics, Stanford University, Stanford, United States
Department of Neuroscience, Baylor College of Medicine, Houston, United States
Mariya Chavarha
Department of Neurobiology, Stanford University, Stanford, United States; Department of Bioengineering, Stanford University, Stanford, United States; Department of Pediatrics, Stanford University, Stanford, United States
Ying Yang
Department of Neurobiology, Stanford University, Stanford, United States; Department of Bioengineering, Stanford University, Stanford, United States; Department of Pediatrics, Stanford University, Stanford, United States
Department of Neurobiology, Stanford University, Stanford, United States; Department of Bioengineering, Stanford University, Stanford, United States; Department of Pediatrics, Stanford University, Stanford, United States
Department of Bioengineering, Stanford University, Stanford, United States; Department of Pediatrics, Stanford University, Stanford, United States; Department of Neuroscience, Baylor College of Medicine, Houston, United States
Monitoring voltage dynamics in defined neurons deep in the brain is critical for unraveling the function of neuronal circuits but is challenging due to the limited performance of existing tools. In particular, while genetically encoded voltage indicators have shown promise for optical detection of voltage transients, many indicators exhibit low sensitivity when imaged under two-photon illumination. Previous studies thus fell short of visualizing voltage dynamics in individual neurons in single trials. Here, we report ASAP2s, a novel voltage indicator with improved sensitivity. By imaging ASAP2s using random-access multi-photon microscopy, we demonstrate robust single-trial detection of action potentials in organotypic slice cultures. We also show that ASAP2s enables two-photon imaging of graded potentials in organotypic slice cultures and in Drosophila. These results demonstrate that the combination of ASAP2s and fast two-photon imaging methods enables detection of neural electrical activity with subcellular spatial resolution and millisecond-timescale precision.
