MiniFAST: a sensitive and fast miniaturized microscope for in vivo neural recording

Jill Juneau; Guillaume Duret; Joshua P Chu; Blake Madruga; Conor C Dorian; Alexander V Rodriguez; Savva Morozov; Daniel Aharoni; Jacob T Robinson; François St-Pierre; Peyman Golshani; Caleb Kemere

doi:10.1117/1.NPh.13.S2.S23203

MiniFAST: a sensitive and fast miniaturized microscope for in vivo neural recording

Neurophotonics. 2026 Feb;13(Suppl 2):S23203. doi: 10.1117/1.NPh.13.S2.S23203. Epub 2026 Mar 14.

Authors

Jill Juneau^{1

2}, Guillaume Duret¹, Joshua P Chu¹, Blake Madruga^{3

4}, Conor C Dorian³, Alexander V Rodriguez¹, Savva Morozov^{1

5}, Daniel Aharoni³, Jacob T Robinson^{1

6

7}, François St-Pierre^{1

7}, Peyman Golshani^{3

8

9}, Caleb Kemere^{1

2

3}

Affiliations

¹ Rice University, Department of Electrical and Computer Engineering, Houston, Texas, United States.
² Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, Cambridge, Massachusetts, United States.
³ University of California, Los Angeles, Department of Neurology, David Geffen School of Medicine, Los Angeles, California, United States.
⁴ Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States.
⁵ Massachusetts Institute of Technology, Computer Science and Artificial Intelligence Laboratory, Cambridge, Massachusetts, United States.
⁶ Rice University, Department of Bioengineering, Houston, Texas, United States.
⁷ Baylor College of Medicine, Department of Neuroscience, Houston, Texas, United States.
⁸ UCLA, Semel Institute for Neuroscience and Human Behavior, Los Angeles, California, United States.
⁹ GLAVA Medical Center, Los Angeles, California, United States.

Abstract

Significance: Observing the activity of large populations of neurons in vivo is critical for understanding brain function and dysfunction. The use of fluorescent genetically encoded calcium indicators (GECIs) in conjunction with miniaturized microscopes is an exciting emerging toolset for recording neural activity in unrestrained animals. Despite their potential, current miniaturized microscope designs are limited using image sensors with low frame rates, sensitivity, and resolution. Beyond GECIs, there are many neuroscience applications that would benefit from the use of other emerging neural indicators, such as fluorescent genetically encoded voltage indicators (GEVIs) that have faster temporal resolution to match neuron spiking, yet require imaging at high speeds.

Aim: We integrated an advanced CMOS image sensor into a popular open-source one-photon miniaturized microscope platform.

Approach: MiniFAST is a fast and sensitive miniaturized microscope capable of 1080p video ( $1920 \times 1080 pixels$ ), $1.5 μ m$ resolution, frame rates up to 500 Hz (achieved with windowing: $1920 \times 55 pixels$ height), and high gain ability (up to 70 dB) to image in extremely low-light conditions.

Results: We report results of $\sim 300 - Hz$ in vivo imaging of freely behaving transgenic Thy1-GCaMP6f mice, high-speed 500-Hz in vitro imaging of a GEVI, and in vivo GEVI imaging in head-fixed mice.

Conclusions: Our results extend miniaturized microscope capabilities in high-speed imaging, high sensitivity, and increased resolution.

Keywords: Sony STARVIS; genetically encoded calcium indicators; genetically encoded voltage indicators; hippocampus; miniaturized microscopes; neuroengineering tools; open-source.