Fast two-photon imaging of subcellular voltage dynamics in neuronal tissue with genetically encoded indicators

• Published in: eLife Vol. 6
• Main Authors: Chamberland, Simon, Yang, Helen H, Pan, Michael M, Evans, Stephen W, Guan, Sihui, Chavarha, Mariya, Yang, Ying, Salesse, Charleen, Wu, Haodi, Wu, Joseph C, Clandinin, Thomas R, Toth, Katalin, Lin, Michael Z, St-Pierre, François
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 27.07.2017; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: Action Potentials - physiology; Animals; Cell regulation; Datasets; Diagnostic imaging; Drosophila melanogaster - genetics; Drosophila melanogaster - metabolism; Drosophila Proteins - genetics; Electric fields; Female; Genetic aspects; genetically encoded voltage indicators; HEK293 Cells; Humans; Hypotheses; Image Processing, Computer-Assisted - methods; Innovations; Male; Microscopy; Nerve Tissue Proteins - genetics; Neural circuitry; Neuroimaging; Neurons - cytology; Neurons - physiology; Neuroscience; Neurosciences; Noise; Optogenetics; Organ Culture Techniques; Photons; random-access multiphoton imaging; Rats, Sprague-Dawley; Rats, Wistar; Sensors; Spatial discrimination; Subcellular Fractions; Tools and Resources; Voltage; voltage imaging; Voltage-Sensitive Dye Imaging - methods; random-access multiphoton imaging; genetically encoded voltage indicators; mouse; voltage imaging; D. melanogaster; neuroscience
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.25690

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 . 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.