Miniaturized widefield microscope for high speed in vivo voltage imaging

Area of Science:

• Neuroscience
• Biomedical Engineering
• Optical Imaging

Background:

• Functional imaging in freely moving animals is crucial for understanding neural activity's behavioral relevance.
• Genetically encoded voltage indicators (GEVIs) offer high spatial and temporal precision but require advanced imaging systems.
• Miniaturizing efficient, high-speed imaging systems for voltage imaging has been a significant challenge.

Purpose of the Study:

• To develop a miniaturized microscope for high-performance in vivo voltage imaging.
• To overcome the challenges of insufficient collection efficiency and slow frame rates in current systems.
• To enable precise study of neural activity correlated with behavior.

Main Methods:

• Designed a miniaturized microscope with a numerical aperture of 0.6 and a 250 µm field of view.
• Achieved a working distance of 1.3-1.6 mm and a total weight of 16.4 g.
• Utilized genetically encoded voltage indicators (GEVIs) for fluorescence-based voltage sensing.

Main Results:

• Successfully imaged in vivo voltage spikes from Voltron2.
• Achieved a spike peak-to-noise ratio greater than 3.
• Operated the system at a high frame rate of 530 Hz.

Conclusions:

• The developed miniaturized microscope enables high-fidelity voltage imaging in freely moving animals.
• This technology overcomes previous limitations in imaging system miniaturization and speed.
• It opens new avenues for correlating neural dynamics with behavior at unprecedented precision.