# Deep brain fluorescence imaging with minimally invasive ultra-thin optical fibers

## TL;DR

This paper introduces a minimally invasive ultrathin multimode optical fiber microendoscope capable of high-resolution, multispectral, and volumetric neural imaging at arbitrary depths in vivo, surpassing current limitations of existing methods.

## Contribution

The study presents a novel ultrathin multimode fiber microendoscope that enables deep, cellular-resolution neural imaging with improved speed and minimal tissue damage, advancing neuroscience research capabilities.

## Key findings

- Achieved micron-scale resolution in deep brain regions.
- Demonstrated multispectral and volumetric imaging capabilities.
- Captured rapid neuronal dynamics in vivo in rodents.

## Abstract

A major open challenge in neuroscience is the ability to measure and perturb neural activity in vivo from well-defined neural sub-populations at cellular resolution anywhere in the brain. However, limitations posed by scattering and absorption prohibit non-invasive (surface) multiphoton approaches for deep (>2mm) structures, while Gradient Refreactive Index (GRIN) endoscopes are thick and cause significant damage upon insertion. Here, we demonstrate a novel microendoscope to image neural activity at arbitrary depths via an ultrathin multimode optical fiber (MMF) probe that is 5-10X thinner than commercially available microendoscopes. We demonstrate micron-scale resolution, multispectral and volumetric imaging. In contrast to previous approaches, we show that this method has an improved acquisition speed that is sufficient to capture rapid neuronal dynamics in-vivo in rodents expressing a genetically encoded calcium indicator. Our results emphasize the potential of this technology in neuroscience applications and open up possibilities for cellular resolution imaging in previously unreachable brain regions.

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Source: https://tomesphere.com/paper/1703.07633