Fourier light field polarization microscopy for depth-resolved fluorescence imaging of brain tissue slices

Understanding the three-dimensional organization of brain microstructure is essential for revealing the functional relationships between neurons and glial cells. We have constructed a Fourier Light Field Fluorescence Polarization Microscopy (FLF-FPM) system that can reconstruct the volumetric distribution of six Stokes-derived polarization parameters, enabling scan-less three-dimensional tomographic imaging of fluorescence intensity and polarization. Applied to ex-vivo mouse brain samples stained with GFP, NeuN, and Iba1, the system reveals distinct depth-dependent polarization signatures for each fluorophore label, reflecting both their intrinsic emission characteristics and tissue scattering effects. FLF-FPM provides a compact, low-cost, and quantitative approach for characterizing cellular morphology, layer-specific organization, and local optical anisotropy in thick brain tissue, offering a new, to the best of our knowledge, platform for investigating the structural basis of neural function.