Large-scale voltage imaging in behaving mice using targeted illumination
Sheng Xiao,
Eric Lowet,
Howard J. Gritton,
Pierre Fabris,
Yangyang Wang,
Jack Sherman,
Rebecca A. Mount,
Hua-an Tseng,
Heng-Ye Man,
Christoph Straub,
Kiryl D. Piatkevich,
Edward S. Boyden,
Jerome Mertz,
Xue Han
Affiliations
Sheng Xiao
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Eric Lowet
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Howard J. Gritton
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Department of Comparative Biosciences, University of Illinois, Urbana, IL 61802, USA
Pierre Fabris
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Yangyang Wang
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Jack Sherman
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Rebecca A. Mount
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Hua-an Tseng
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Heng-Ye Man
Department of Biology, Boston University, Boston, MA 02215, USA
Christoph Straub
Department of Biomedical Sciences, College of Osteopathic Medicine, University of New England, Biddeford, ME 04005, USA
Kiryl D. Piatkevich
School of Life Sciences, Westlake University, Westlake Laboratory of Life Sciences and Biomedicine, Westlake Institute for Advanced Study, Hangzhou, Zhejiang, China
Edward S. Boyden
MIT McGovern Institute for Brain Research, MIT, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, MIT, Cambridge, MA 02139, USA
Jerome Mertz
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
Xue Han
Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Corresponding author
Summary: Recent improvements in genetically encoded voltage indicators enabled optical imaging of action potentials and subthreshold transmembrane voltage in vivo. To perform high-speed voltage imaging of many neurons simultaneously over a large anatomical area, widefield microscopy remains an essential tool. However, the lack of optical sectioning makes widefield microscopy prone to background cross-contamination. We implemented a digital-micromirror-device-based targeted illumination strategy to restrict illumination to the cells of interest and quantified the resulting improvement both theoretically and experimentally with SomArchon expressing neurons. We found that targeted illumination increased SomArchon signal contrast, decreased photobleaching, and reduced background cross-contamination. With the use of a high-speed, large-area sCMOS camera, we routinely imaged tens of spiking neurons simultaneously over minutes in behaving mice. Thus, the targeted illumination strategy described here offers a simple solution for widefield voltage imaging of many neurons over a large field of view in behaving animals.
