Minimally invasive multimode optical fiber microendoscope for deep brain fluorescence imaging

Area of Science:

• Neuroscience
• Biomedical Engineering
• Optical Imaging

Background:

• Current in vivo neuroscience tools struggle with cellular-resolution imaging deep within the brain due to light scattering and absorption.
• Existing methods like multi-photon microscopy are limited to superficial structures (>2mm), and gradient refractive index (GRIN) endoscopes are too thick and invasive.

Purpose of the Study:

• To develop a novel micro-endoscope for high-resolution neural activity imaging at arbitrary depths within the brain.
• To overcome the limitations of existing technologies for deep brain circuit investigation.

Main Methods:

• Development of an ultra-thin multi-mode optical fiber (MMF) probe with a 5-10X smaller diameter than conventional micro-endoscopes.
• Demonstration of micron-scale resolution, multi-spectral, and volumetric imaging capabilities.
• In vivo validation in rodents using genetically encoded calcium indicators (e.g., GCaMP).

Main Results:

• Achieved cellular-resolution imaging at arbitrary depths, surpassing the limitations of current deep brain imaging techniques.
• Demonstrated high-speed acquisition rates sufficient for capturing rapid neuronal dynamics.
• Validated the micro-endoscope's efficacy in live animal models.

Conclusions:

• The novel ultra-thin MMF micro-endoscope offers a significant advancement for in vivo neuroscience research.
• This technology enables unprecedented cellular-level access to previously unreachable brain regions, facilitating deeper understanding of neural circuits.