# Large-field-of-view high-throughput two-photon endoscope to image neuronal activity

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA AT DAVIS · 2020 · $1,447,134

## Abstract

Project Summary
Large-field-of-view high-throughput two-photon endoscope to image neuronal activity
Development of miniaturized optical endoscopes have enabled visualization and recording of neural activity
in freely-behaving animals. Two-photon endoscopes have excellent signal-to-background ratio, and can
image deep into the tissue. It has a good optical sectioning and low phototoxicity. However, two-photon
endoscopes have a very limited field of view and imaging throughput, and cannot typically perform axial
refocusing for 3D imaging. These technological bottlenecks have so far prevented two-photon endoscopes’
broad deployment in neuroscience studies, particularly in the investigation of large scale neuronal circuits in
freely-behaving animals.
Here, we propose a two-photon endoscope that can image neural activity over a large field of view
(~1.32x1.32 mm2) with high spatiotemporal resolution (>10 Hz, cellular resolution). This represents >35x
increase of field of view, and >25x increase of image throughput than the state-of-the-art two-photon
endoscopes. Furthermore, the proposed endoscope could perform fast refocusing, enabling multiplane 3D
imaging. Our optical and mechanical design also ensures the compactness and lightweight of the
endoscope. Such a two-photon endoscope will revolutionize the design principle of multiphoton endoscopes,
and could play an important role in the investigation of large scale neuronal circuits in freely-behaving animals.
This proposal overcomes the current technological bottlenecks in two-photon endoscopes by multiple
innovations: (1) To achieve a large field of view with fine spatial resolution, the dimensions of the optics are
typically large. We will custom design and optimize all the optical components, and make the whole package
to be <~1.6x1x1 cm3. (2) To maintain a high spatial resolution, the imaging speed could be very low in
conventional laser scanning microscopy as a diffraction limited spot is used as the sampling pattern. Here,
we will increase the sampling spot size to a large square, and use computation algorithms to achieve super
resolution (to cellular resolution). We meanwhile use temporal focusing technique to achieve a tight axial
confinement. (3) We will employ a tunable liquid lens for fast axial refocusing. (4) While we do not foresee a
large weight of the endoscope, we will use an active feedback mechanical design to greatly reduce its weight,
and thus reduce the load burden on the animal.
The proposed endoscope will greatly benefit the neuroscience community, be deployed to many research
labs, and enable new research that were previously not possible. While we will design and test it for mice, its
application could also be extended to rats and non-human primates in the future.

## Key facts

- **NIH application ID:** 10047830
- **Project number:** 1R01NS118289-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA AT DAVIS
- **Principal Investigator:** Weijian Yang
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $1,447,134
- **Award type:** 1
- **Project period:** 2020-09-30 → 2024-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10047830

## Citation

> US National Institutes of Health, RePORTER application 10047830, Large-field-of-view high-throughput two-photon endoscope to image neuronal activity (1R01NS118289-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10047830. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*