Voltage imaging with periodic structured illumination

Area of Science:

• Neuroscience
• Optical Imaging
• Biophysics

Background:

• In vivo voltage imaging is crucial for understanding neural circuit dynamics.
• Out-of-focus cellular signals can contaminate recordings, reducing the accuracy of voltage activity measurements.
• Traditional widefield imaging and pseudo-widefield (pWF) reconstructions struggle to mitigate this out-of-focus light effectively.

Purpose of the Study:

• To evaluate the efficacy of periodic structured illumination with pseudo-HiLo (pHiLo) image reconstruction for in vivo voltage imaging.
• To compare the performance of pHiLo against traditional widefield recordings and pseudo-widefield (pWF) reconstructions in reducing out-of-focus signals.
• To assess the impact of pHiLo on key imaging metrics such as spike peak-to-noise ratio (PNR) and cell-background correlation.

Main Methods:

• Utilized periodic structured illumination with pseudo-HiLo (pHiLo) image reconstruction.
• Performed in vivo voltage imaging experiments.
• Compared pHiLo with traditional widefield illumination and pseudo-widefield (pWF) reconstructions.
• Analyzed spike peak-to-noise ratio (PNR) and cell-background correlation for time courses.

Main Results:

• pHiLo significantly reduced signal from out-of-focus cells compared to traditional widefield recordings and pWF reconstructions.
• Demonstrated improved clarity of voltage activity for in-focus cells of interest using pHiLo.
• Quantitative comparisons of PNR and cell-background correlation were made between pHiLo and soma-targeted widefield illumination (TI).

Conclusions:

• pHiLo is an effective technique for reducing out-of-focus light contamination in high-speed in vivo voltage imaging.
• The study highlights the tradeoffs between out-of-focus light reduction, signal-to-noise ratio, and temporal resolution with pHiLo.
• pHiLo offers advantages for imaging neural activity in awake mice by enhancing signal quality.