– 8 Future Developments Likely to Increase the Value of Wide-Field Mesoscopes in Neuroscience Research
In our previous blog post, we explored recent studies where wide-field imaging played a crucial role. In this post, we shift our focus toward some of the most promising advancements in wide-field macroscope (or “mesoscope”) technology that are poised to transform neuroscientific research in the coming years, based on current technological trends, possibilities, and research demands.
- More Selective Targeting of Neuronal Subtypes and Functional Parameters
The repertoire of genetically-expressed fluorescent reporters continues to expand rapidly. This growth provides new options for selectively targeting specific cell types and measuring physiological parameters previously inaccessible. Additionally, advances in the optical properties and molecular kinetics of these reporters enable experimental designs that were once deemed impractical.
- Multi-Channel Imaging
The development of these reporters alongside improvements in wide-field macroscope hardware and software, allow researchers to simultaneously image multiple reporters. This capability enables the investigation of
- Voltage-Sensitive Dyes (VSDs) and Faster, Higher-Resolution Cameras
While closely related to the points above, this topic deserves its own category. There is renewed interest in refining genetically-expressed voltage-sensitive reporters. Their utility in wide-field mesoscopy has been enhanced by the advent of cameras with increased sensitivity and frame rates, without sacrificing image resolution.
- Imaging Deeper Neuronal Layers
Wide-field mesoscopes excel at capturing data from superficial cortical layers, but scattering has historically limited their effectiveness in deeper brain regions. However, recent and forthcoming advancements, such as the development of red-shifted dyes and reporters, are reducing scattering and improving image quality at greater depths.
The selective expression of fluorescent reporters, which eliminates signals from layers above and below the target area, further enhances imaging precision at depth.
Additionally, improved signal processing algorithms help to filter out noise while amplifying signals of interest.
Another approach was demonstrated in a recent paper, where they employed optical fiber bundles to access deeper layers. This type of approach, combined with surgical innovations and miniaturized transmission optics (e.g., GRIN lenses or miniaturized compound lenses), represent another promising avenue that is expected to evolve.
- Miniaturized Imaging Systems
The functionality and popularity of head-mounted miniscopes have now been extended to mesoscopic fields-of-view. This advancement creates new opportunities to synchronize imaging with behavioral recordings in freely moving animals. While current miniscopes are limited by the optical components that can be integrated without adding significant weight or volume, future developments in micro-manufacturing are expected to further enhance their utility.
- Data Analysis and Machine Learning Integration
Better handling and analysis of the vast datasets generated by wide-field macroscopy and its synchronization with other concurrent data capture modalities (e.g., electrophysiology, behavioral monitoring), are ideally suited for machine learning algorithms. This improved analysis capabilities are bound to offer novel insights into brain function.
- Better Integration of Data Channels
Mesoscopic imaging is often combined with other techniques, such as behavioral analysis or optogenetic and chemogenetic actuators. The precise synchronization of data capture across these modalities, along with the ability to dynamically adjust inputs during experiments, open up new avenues for research. Future developments in control hardware and software will likely offer new options here, potentially incorporating machine learning protocols for enhanced usability.
- Adaptive Optics and New Optics Architecture
Finally, improving image quality by reducing distortions through adaptive optics in the detection path holds great promise. These innovations can sharpen image clarity and resolution, particularly when extracting data from deeper tissue layers.
Collaborative efforts between neuroscience labs and optical engineers or boutique optics manufacturers are likely to yield further advancements in microscope hardware design. A notable example is a recent study in which the excitation light source and detector were aligned with the curvature of the macaque cortex, resulting in high-quality images across a wider field of view.
Feel free to comment below on the other interesting trends and developments we are likely to benefit from in the field of wide-field macroscopy experiments in the years ahead.
