# 3D Scanning Two-photon Fiberscope Technology for Simultaneous Multi-region Multi-cell-type Imaging in Freely-moving Rodents

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2024 · $615,279

## Abstract

PROJECT SUMMARY
Brain activities involve neurons generating fast-propagating signals to encode and relay information within
dynamic neural networks. Neuroscientists aspire to obtain access to such networks in unconstrained animal
models (e.g., rodents) with high spatiotemporal resolution, which will shed light on the fundamental working
mechanisms of the brain. Optical imaging, particularly multiphoton microscopy, has played a significant role in
this endeavor. The past decade has seen impressive progresses, from head-restrained benchtop microscopy
with virtual navigation to large FOV microscopy for neuron population imaging, three-photon microscopy for deep
brain imaging, and two-photon (2P) miniscopy for in vivo imaging in freely-walking (but limited rotation) mice.
Despite these exciting technological advances, tools for simultaneous, large-scale, and high-resolution
imaging over multiple brain regions in freely-behaving rodents are still lacking. Successful development of
such tools can accelerate the process of uncovering general principles of neural networks in a working brain
under nearly natural conditions. The free-moving style for imaging would minimize the differences between
experimentally controlled actions and natural spontaneous behaviors, thus allowing for precise examination of
neural network functions. The capability of simultaneous imaging over two interconnected neural populations
would provide a comprehensive and precise timeline of the neural circuit dynamics associated with various
behaviors at both cellular and population levels.
Our proposed research is motivated by the need for such imaging tools with the above-mentioned features. The
main objective is to develop a 3D-scanning, ultrathin and light 2P fiberscope technology for enabling high-
resolution, simultaneous imaging of dynamic neural activities over a large FOV at two brain regions in freely-
moving rodents. To achieve our objective, we propose the following aims:
(1) To develop a fast scanning 2P fiberscope of a large FOV (Ø500 um) using a cascaded magnification
strategy while maintaining a compact probe size (Ø2.5 mm). The larger FOV will be achieved by using an
innovative micro-optics design. In addition, a modular scanner head design will be implemented in the 2P
fiberscope to improve the probe robustness for in vivo imaging at a high scanning frequency (e.g., ~2.8 kHz);
(2) To develop a miniature (Ø2mm) tunable lens that can be integrated into our 2D scanning fiberscope
for enabling depth (focus) scanning/selection over 150 um. Focus scanning allows for convenient selection
of a proper layer or population of neurons. The tunable lens can create a curved refractive index profile when
applied with a low-voltage (<10 V, safe) electrical drive. Compared with other tunable lenses, the tunable lens
will be extremely compact and light, critical for imaging freely-moving rodents. A fiberscope integrated with a
tunable lens will be developed and tested using phantoms,...

## Key facts

- **NIH application ID:** 10811729
- **Project number:** 5R01EB033364-02
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Xingde Li
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $615,279
- **Award type:** 5
- **Project period:** 2023-04-01 → 2027-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10811729

## Citation

> US National Institutes of Health, RePORTER application 10811729, 3D Scanning Two-photon Fiberscope Technology for Simultaneous Multi-region Multi-cell-type Imaging in Freely-moving Rodents (5R01EB033364-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10811729. Licensed CC0.

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