A Fluorescence Imaging-Based 3D Analysis Pipeline for Mouse Trigeminal Ganglion Neurons.

Area of Science:

• Neuroscience
• Anatomy
• Imaging Technology

Background:

• The trigeminal ganglion (TG) is crucial for processing whisker (vibrissal) touch information.
• Conventional 2D methods limit understanding of the TG's complex 3D structure.
• A detailed 3D map is needed to understand sensory neuron organization within the TG.

Purpose of the Study:

• To develop and validate a 3D imaging workflow for mapping TG cytoarchitecture.
• To profile the spatial distribution of TG neurons innervating specific vibrissae.
• To reveal the 3D organization of TG sensory neurons and their subdomains.

Main Methods:

• Utilized fluorescence micro-optical sectioning tomography (fMOST) for high-resolution 3D imaging of the whole head, including vibrissae and TG.
• Employed propidium iodide (PI) staining for cellular visualization.
• Combined fMOST with retrograde viral/genetic labeling and single-axon tracing to map specific neuronal populations.

Main Results:

• Established a 3D map of TG cytoarchitecture at cellular resolution.
• Identified two distinct subdomains: a neuronal soma-rich region (NSRR) and a fiber-rich region (FRR).
• Demonstrated spatially biased distributions of TG neurons innervating C2, D3, and δ vibrissae within these subdomains, with δ vibrissa neurons showing a broader anteroposterior spread.

Conclusions:

• The fMOST workflow provides unprecedented 3D insights into TG organization.
• Revealed a heterogeneous 3D cytoarchitecture with distinct functional subdomains.
• This study enhances understanding of vibrissal sensory topography and TG functional mechanisms.